Publish

- @0x/contracts-erc20@3.3.31 - @0x/contracts-test-utils@5.4.22 - @0x/contracts-treasury@1.4.14 - @0x/contracts-utils@4.8.12 - @0x/contracts-zero-ex@0.34.0 - @0x/asset-swapper@16.61.0 - @0x/contract-addresses@6.15.0 - @0x/contract-wrappers@13.20.3 - @0x/protocol-utils@11.14.0
Updated CHANGELOGS & MD docs
2022-06-03 19:20:52 +00:00 · 2022-06-03 19:20:49 +00:00 · 2022-06-03 15:03:00 -04:00 · 2022-06-03 15:03:00 -04:00 · 2022-06-03 15:03:00 -04:00 · 2022-06-03 15:03:00 -04:00
3155 changed files with 190920 additions and 202475 deletions
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,300 +1,153 @@
-version: 2
+version: 2.1

 jobs:
    build:
-        resource_class: medium+
+        resource_class: xlarge
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        environment:
-            CONTRACTS_COMMIT_HASH: '9ed05f5'
+            NODE_OPTIONS: '--max-old-space-size=16384'
        working_directory: ~/repo
        steps:
            - checkout
            - run: echo 'export PATH=$HOME/CIRCLE_PROJECT_REPONAME/node_modules/.bin:$PATH' >> $BASH_ENV
            - run:
                  name: install-yarn
-                  command: sudo npm install --global yarn@1.9.4
+                  command: npm install --force --global yarn@1.22.0
            - run:
                  name: yarn
-                  command: yarn --frozen-lockfile --ignore-engines install
-            - run: yarn build:ci:no_website
-            - run: yarn build:ts
+                  command: yarn --frozen-lockfile --ignore-engines install || yarn --frozen-lockfile --ignore-engines install
+            - setup_remote_docker
+            - run: yarn build:ci || yarn build:ci || yarn build:ci || yarn build:ci || yarn build:ci || yarn build:ci
            - save_cache:
                  key: repo-{{ .Environment.CIRCLE_SHA1 }}
                  paths:
                      - ~/repo
-    build-website:
+            - store_artifacts:
+                  path: ~/repo/packages/abi-gen/test-cli/output
+            - store_artifacts:
+                  path: ~/repo/packages/contract-wrappers/generated_docs
+    test-exchange-ganache:
        resource_class: medium+
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        working_directory: ~/repo
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: cd packages/website && yarn build:prod
-    test-contracts-ganache:
+            - run: yarn wsrun -p @0x/contracts-exchange -m --serial -c test:circleci
+    test-integrations-ganache:
+        resource_class: medium+
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        working_directory: ~/repo
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn wsrun test:circleci @0x/contracts-multisig
-            - run: yarn wsrun test:circleci @0x/contracts-utils
-            - run: yarn wsrun test:circleci @0x/contracts-libs
-            - run: yarn wsrun test:circleci @0x/contracts-tokens
-            - run: yarn wsrun test:circleci @0x/contracts-extensions
-            - run: yarn wsrun test:circleci @0x/contracts-protocol
-    test-contracts-geth:
+            - run: yarn wsrun -p @0x/contracts-integrations -m --serial -c test:circleci
+    test-contracts-staking-ganache:
+        resource_class: medium+
        docker:
-            - image: circleci/node:9-browsers
-            - image: 0xorg/devnet
+            - image: node:16
        working_directory: ~/repo
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            # HACK(albrow): we need to sleep 10 seconds to ensure the devnet is
-            # initialized
-            - run: sleep 10 && TEST_PROVIDER=geth yarn wsrun test @0x/contracts-multisig
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-utils
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-libs
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-tokens
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-extensions
-            - run: TEST_PROVIDER=geth yarn wsrun test @0x/contracts-protocol
+            - run: yarn wsrun -p @0x/contracts-staking -m --serial -c test:circleci
+    test-contracts-extra-ganache:
+        resource_class: medium+
+        docker:
+            - image: node:16
+        working_directory: ~/repo
+        steps:
+            - restore_cache:
+                  keys:
+                      - repo-{{ .Environment.CIRCLE_SHA1 }}
+            - run: yarn wsrun -p @0x/contracts-exchange-forwarder -p @0x/contracts-coordinator -m --serial -c test:circleci
+    test-contracts-rest-ganache:
+        resource_class: medium+
+        docker:
+            - image: node:16
+        working_directory: ~/repo
+        steps:
+            - restore_cache:
+                  keys:
+                      - repo-{{ .Environment.CIRCLE_SHA1 }}
+            - run: yarn wsrun -p @0x/contracts-multisig -p @0x/contracts-utils -p @0x/contracts-exchange-libs -p  @0x/contracts-erc20 -p @0x/contracts-erc721 -p @0x/contracts-erc1155 -p @0x/contracts-asset-proxy -p @0x/contracts-broker -p @0x/contracts-zero-ex -m --serial -c test:circleci
    test-publish:
-        resource_class: medium+
+        resource_class: large
+        environment:
+            NODE_OPTIONS: '--max-old-space-size=6442'
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
            - image: 0xorg/verdaccio
        working_directory: ~/repo
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn test:publish:circleci
+            - run:
+                  command: yarn test:publish:circleci
+                  no_output_timeout: 1800
+            - store_artifacts:
+                  path: ~/.npm/_logs
    test-doc-generation:
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        working_directory: ~/repo
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn test:generate_docs:circleci
-    test-pipeline:
-        docker:
-            - image: circleci/node:9
-            - image: postgres:11-alpine
-        working_directory: ~/repo
-        steps:
-            - restore_cache:
-                  keys:
-                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: ZEROEX_DATA_PIPELINE_TEST_DB_URL='postgresql://postgres@localhost/postgres' yarn wsrun test:circleci @0x/pipeline
-            - save_cache:
-                  key: coverage-pipeline-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/pipeline/coverage/lcov.info
+            - run:
+                  command: yarn test:generate_docs:circleci
+                  no_output_timeout: 1200
    test-rest:
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        working_directory: ~/repo
+        environment:
+            RUST_ROUTER: 'true'
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
-            - run: yarn wsrun test:circleci @0x/contracts-test-utils
-            - run: yarn wsrun test:circleci @0x/abi-gen
-            - run: yarn wsrun test:circleci @0x/assert
-            - run: yarn wsrun test:circleci @0x/base-contract
-            - run: yarn wsrun test:circleci @0x/connect
-            - run: yarn wsrun test:circleci @0x/contract-wrappers
-            - run: yarn wsrun test:circleci @0x/dev-utils
-            - run: yarn wsrun test:circleci @0x/json-schemas
-            - run: yarn wsrun test:circleci @0x/metacoin
-            - run: yarn wsrun test:circleci @0x/order-utils
-            - run: yarn wsrun test:circleci @0x/order-watcher
-            - run: yarn wsrun test:circleci @0x/sol-compiler
-            - run: yarn wsrun test:circleci @0x/sol-tracing-utils
-            - run: yarn wsrun test:circleci @0x/sol-doc
-            - run: yarn wsrun test:circleci @0x/subproviders
-            - run: yarn wsrun test:circleci @0x/web3-wrapper
-            - run: yarn wsrun test:circleci @0x/utils
-            - run: yarn wsrun test:circleci @0x/instant
+            - run: yarn wsrun -p @0x/contracts-test-utils -m --serial -c test:circleci
+            - run: yarn wsrun -p @0x/contract-artifacts -m --serial -c test:circleci
+            - run: yarn wsrun -p @0x/contract-wrappers-test -m --serial -c test:circleci
+            - run: yarn wsrun -p @0x/order-utils -m --serial -c test:circleci
+            - run: yarn wsrun -p @0x/asset-swapper -m --serial -c test:circleci
            - save_cache:
-                  key: coverage-abi-gen-{{ .Environment.CIRCLE_SHA1 }}
+                  key: coverage-contract-wrappers-test-{{ .Environment.CIRCLE_SHA1 }}
                  paths:
-                      - ~/repo/packages/abi-gen/coverage/lcov.info
-            - save_cache:
-                  key: coverage-assert-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/assert/coverage/lcov.info
-            - save_cache:
-                  key: coverage-base-contract-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/base-contract/coverage/lcov.info
-            - save_cache:
-                  key: coverage-connect-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/connect/coverage/lcov.info
-            - save_cache:
-                  key: coverage-contract-wrappers-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/contract-wrappers/coverage/lcov.info
-            - save_cache:
-                  key: coverage-dev-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/dev-utils/coverage/lcov.info
-            - save_cache:
-                  key: coverage-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/json-schemas/coverage/lcov.info
-            - save_cache:
-                  key: coverage-metacoin-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/metacoin/coverage/lcov.info
+                      - ~/repo/packages/contract-wrappers-test/coverage/lcov.info
            - save_cache:
                  key: coverage-order-utils-{{ .Environment.CIRCLE_SHA1 }}
                  paths:
                      - ~/repo/packages/order-utils/coverage/lcov.info
-            - save_cache:
-                  key: coverage-order-watcher-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/order-watcher/coverage/lcov.info
-            - save_cache:
-                  key: coverage-sol-compiler-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/sol-compiler/coverage/lcov.info
-            - save_cache:
-                  key: coverage-sol-tracing-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/sol-tracing-utils/coverage/lcov.info
-            - save_cache:
-                  key: coverage-sol-doc-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/sol-doc/coverage/lcov.info
-            - save_cache:
-                  key: coverage-subproviders-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/packages/subproviders/coverage/lcov.info
            - save_cache:
                  key: coverage-web3-wrapper-{{ .Environment.CIRCLE_SHA1 }}
                  paths:
                      - ~/repo/packages/web3-wrapper/coverage/lcov.info
-    test-python:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/python
-            - image: 0xorg/ganache-cli:2.2.2
-            - image: 0xorg/launch-kit-ci
-              command: |
-                  yarn start:ts -p 3000:3000
-        steps:
-            - checkout
-            - run: sudo chown -R circleci:circleci /usr/local/bin
-            - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
-            - restore_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-            - run:
-                  command: |
-                      cd python-packages
-                      python -m ensurepip
-                      ./install
-            - save_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - '/usr/local/bin'
-                      - '/usr/local/lib/python3.7/site-packages'
-            - run:
-                  command: |
-                      cd python-packages
-                      ./cmd_pkgs_in_dep_order.py coverage run setup.py test
-            - save_cache:
-                  key: coverage-python-contract-addresses-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/contract_addresses/.coverage
-            - save_cache:
-                  key: coverage-python-contract-artifacts-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/contract_artifacts/.coverage
-            - save_cache:
-                  key: coverage-python-contract-demo-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/contract_demo/.coverage
-            - save_cache:
-                  key: coverage-python-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/json_schemas/.coverage
-            - save_cache:
-                  key: coverage-python-order-utils-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/order_utils/.coverage
-            - save_cache:
-                  key: coverage-python-sra-client-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - ~/repo/python-packages/sra_client/.coverage
-    test-rest-python:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/python
-        steps:
-            - checkout
-            - run: sudo chown -R circleci:circleci /usr/local/bin
-            - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
-            - restore_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-            - run:
-                  command: |
-                      cd python-packages/order_utils
-                      python -m ensurepip
-                      python -m pip install .
-            - save_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-                  paths:
-                      - '/usr/local/bin'
-                      - '/usr/local/lib/python3.7/site-packages'
-                      - '.eggs'
-                      - '.mypy_cache'
-                      - '.pytest_cache'
-                      - '.tox'
-            - run:
-                  command: |
-                      cd python-packages/order_utils
-                      tox
-    static-tests-python:
-        working_directory: ~/repo
-        docker:
-            - image: circleci/python
-        steps:
-            - checkout
-            - run: sudo chown -R circleci:circleci /usr/local/bin
-            - run: sudo chown -R circleci:circleci /usr/local/lib/python3.7/site-packages
-            - restore_cache:
-                  key: deps9-{{ .Branch }}-{{ .Environment.CIRCLE_SHA1 }}
-            - run:
-                  command: |
-                      python -m ensurepip
-                      cd python-packages
-                      ./install
-                      ./lint
    static-tests:
+        resource_class: large
        working_directory: ~/repo
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        steps:
            - restore_cache:
                  keys:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
            - run: yarn lerna run lint
            - run: yarn prettier:ci
-            - run: cd packages/0x.js && yarn build:umd:prod
-            - run: yarn bundlewatch
+            - run: yarn deps_versions:ci
+            - run: yarn diff_md_docs:ci
    submit-coverage:
        docker:
-            - image: circleci/node:9-browsers
+            - image: node:16
        working_directory: ~/repo
        steps:
            - restore_cache:
@@ -302,86 +155,33 @@ jobs:
                      - repo-{{ .Environment.CIRCLE_SHA1 }}
            - restore_cache:
                  keys:
-                      - coverage-abi-gen-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-assert-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-base-contract-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-connect-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-contract-wrappers-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-dev-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-metacoin-{{ .Environment.CIRCLE_SHA1 }}
+                      - coverage-contract-wrappers-test-{{ .Environment.CIRCLE_SHA1 }}
            - restore_cache:
                  keys:
                      - coverage-order-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-order-watcher-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-sol-compiler-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-sol-tracing-utils-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-sol-doc-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-subproviders-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-web3-wrapper-{{ .Environment.CIRCLE_SHA1 }}
            - restore_cache:
                  keys:
                      - coverage-contracts-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-json-schemas-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-contract-addresses-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-contract-artifacts-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-contract-demo-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-sra-client-{{ .Environment.CIRCLE_SHA1 }}
-            - restore_cache:
-                  keys:
-                      - coverage-python-order-utils-{{ .Environment.CIRCLE_SHA1 }}
            - run: yarn report_coverage
 workflows:
    version: 2
    main:
        jobs:
            - build
-            - build-website:
-                  requires:
-                      - build
-            - test-contracts-ganache:
-                  requires:
-                      - build
-            - test-contracts-geth:
-                  requires:
-                      - build
-            - test-pipeline:
+            # Disabled until we begin actively developing on these packages again.
+            # - test-exchange-ganache:
+            #       requires:
+            #           - build
+            # - test-integrations-ganache:
+            #       requires:
+            #           - build
+            # - test-contracts-staking-ganache:
+            #       requires:
+            #           - build
+            # - test-contracts-extra-ganache:
+            #       requires:
+            #           - build
+            - test-contracts-rest-ganache:
                  requires:
                      - build
            - test-rest:
@@ -396,13 +196,14 @@ workflows:
            - test-doc-generation:
                  requires:
                      - build
-            - submit-coverage:
-                  requires:
-                      - test-rest
-                      - test-python
-            - static-tests-python:
-                  requires:
-                      - test-python
-            - test-python
-            # skip python tox run for now, as we don't yet have multiple test environments to support.
-            #- test-rest-python
+            # Disabled until this repo has a coveralls API key
+            # - submit-coverage:
+            #       requires:
+            #           # Disabled until we begin actively developing on these packages again.
+            #           # - test-exchange-ganache
+            #           # - test-integrations-ganache
+            #           # - test-contracts-staking-ganache
+            #           # - test-contracts-extra-ganache
+            #           - test-contracts-rest-ganache
+            #           - test-rest
+            #           - static-tests
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,7 +1,4 @@
 *.sol linguist-language=Solidity

 # Automatically collapse generated files in GitHub.
-*.svg linguist-generated
-packages/contract-artifacts/artifacts/*json linguist-generated
-packages/abi-gen-wrappers/wrappers/*.ts liguist-generated
-
+*.svg linguist-generated=true
--- a/.github/autolabeler.yml
+++ b/.github/autolabeler.yml
@@ -1,42 +1,6 @@
 python: ['python-packages']
 contracts: ['contracts']
-sol-doc: ['packages/sol-doc']
-sol-resolver: ['packages/sol-resolver']
-sra-spec: ['packages/sra-spec']
-subproviders: ['packages/subproviders']
-contract-addresses: ['packages/contract-addresses']
-migrations: ['packages/migrations']
-web3-wrapper: ['packages/web3-wrapper']
-sol-compiler: ['packages/sol-compiler']
-types: ['packages/types']
-instant: ['packages/instant']
-abi-gen-templates: ['packages/abi-gen-templates']
-abi-gen: ['packages/abi-gen']
-website: ['packages/website']
-sol-coverage: ['packages/sol-coverage']
-sol-profiler: ['packages/sol-profiler']
-sol-trace: ['packages/sol-trace']
-sol-tracing-utils: ['packages/sol-tracing-utils']
-utils: ['packages/utils']
-tslint-config: ['packages/tslint-config']
-asset-buyer: ['packages/asset-buyer']
-order-watcher: ['packages/order-watcher']
-react-docs: ['packages/react-docs']
-order-utils: ['packages/order-utils']
-react-shared: ['packages/react-shared']
-assert: ['packages/assert']
-base-contract: ['packages/base-contract']
-typescript-typings: ['packages/typescript-typings']
-0x.js: ['packages/0x.js']
-abi-gen-wrappers: ['packages/abi-gen-wrappers']
-metacoin: ['packages/metacoin']
-contract-artifacts: ['packages/contract-artifacts']
-dev-utils: ['packages/dev-utils']
-contract-wrappers: ['packages/contract-wrappers']
-json-schemas: ['packages/json-schemas']
-ethereum-types: ['ethereum-types']
-connect: ['packages/connect']
-fill-scenarios: ['packages/fill-scenarios']
-dev-tools-pages: ['packages/dev-tools-pages']
-testnet-faucets: ['packages/testnet-faucets']
-monorepo-scripts: ['packages/monorepo-scripts']
+@0x/contract-addresses: ['packages/contract-addresses']
+@0x/order-utils: ['packages/order-utils']
+@0x/contract-artifacts: ['packages/contract-artifacts']
+@0x/contract-wrappers: ['packages/contract-wrappers']
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -0,0 +1,53 @@
+name: publish
+
+on:
+  workflow_dispatch:
+      inputs:
+          ci_status:
+              description: 'required CI status'
+              default: 'success'
+              required: true
+          prerelease:
+              description: 'prerelease name'
+              required: false
+
+jobs:
+    publish:
+        runs-on: ubuntu-latest
+        steps:
+            - name: 'check successful status'
+              run: |
+                  REF_STATUS=$(curl -s \
+                  'https://api.github.com/repos/${{ github.repository }}/commits/${{ github.ref }}/status' \
+                  | jq .state)
+                  [[ "${REF_STATUS}" == '"${{ github.event.inputs.ci_status }}"' ]] || \
+                  (echo "::error ::${{ github.ref }} does not have a successful CI status" && false)
+            - uses: actions/checkout@v2
+              with:
+                ref: ${{ github.ref }}
+                fetch-depth: 0
+            - uses: actions/setup-node@v1
+              with:
+                node-version: 16
+            - uses: actions/setup-python@v2
+            - name: 'configure git'
+              run: |
+                  git config --global user.email "github-actions@github.com"
+                  git config --global user.name "Github Actions"
+            - name: 'install dependencies'
+              run: |
+                  yarn -D
+            - name: 'build and publish'
+              run: |
+                  echo '//registry.npmjs.org/:_authToken=${NPM_TOKEN}' > .npmrc
+                  npm run run:publish:gha
+              env:
+                  NPM_TOKEN: ${{ secrets.NPM_PUBLISH_TOKEN }}
+                  GITHUB_TOKEN: ${{ github.token }}
+                  PUBLISH_PRERELEASE: ${{ github.event.inputs.prerelease }}
+            - name: 'merge into main branch'
+              if: github.event.inputs.prerelease == '' # unless it's a prerelease
+              run: |
+                  git checkout main && \
+                  git merge ${{ github.ref }} && \
+                  git push
--- a/.gitignore
+++ b/.gitignore
@@ -40,9 +40,12 @@ build/Release
 node_modules/
 jspm_packages/

-# Typescript v1 declaration files
+# TypeScript v1 declaration files
 typings/

+# NVM config
+.nvmrc
+
 # Optional npm cache directory
 .npm
 .npmrc
@@ -72,52 +75,108 @@ generated_docs/

 TODO.md

-# VSCode file
+# IDE file
 .vscode
-
-packages/website/public/bundle*
-packages/dev-tools-pages/public/bundle*
-packages/react-docs/example/public/bundle*
-
-# server cli
-packages/testnet-faucets/server/
+.idea

 # generated contract artifacts/
-contracts/protocol/generated-artifacts/
+contracts/broker/generated-artifacts/
+contracts/broker/test/generated-artifacts/
+contracts/erc20-bridge-sampler/generated-artifacts/
+contracts/erc20-bridge-sampler/test/generated-artifacts/
+contracts/integrations/generated-artifacts/
+contracts/integrations/test/generated-artifacts/
+contracts/staking/generated-artifacts/
+contracts/staking/test/generated-artifacts/
+contracts/coordinator/generated-artifacts/
+contracts/coordinator/test/generated-artifacts/
+contracts/exchange/generated-artifacts/
+contracts/exchange/test/generated-artifacts/
+contracts/asset-proxy/generated-artifacts/
+contracts/asset-proxy/test/generated-artifacts/
 contracts/multisig/generated-artifacts/
+contracts/multisig/test/generated-artifacts/
 contracts/utils/generated-artifacts/
-contracts/libs/generated-artifacts/
-contracts/interfaces/generated-artifacts/
-contracts/tokens/generated-artifacts/
-contracts/examples/generated-artifacts/
+contracts/utils/test/generated-artifacts/
+contracts/exchange-libs/generated-artifacts/
+contracts/exchange-libs/test/generated-artifacts/
+contracts/erc20/generated-artifacts/
+contracts/erc20/test/generated-artifacts/
+contracts/erc721/generated-artifacts/
+contracts/erc721/test/generated-artifacts/
+contracts/erc1155/generated-artifacts/
+contracts/erc1155/test/generated-artifacts/
 contracts/extensions/generated-artifacts/
-packages/sol-tracing-utils/test/fixtures/artifacts/
-packages/metacoin/artifacts/
+contracts/extensions/test/generated-artifacts/
+contracts/exchange-forwarder/generated-artifacts/
+contracts/exchange-forwarder/test/generated-artifacts/
+contracts/dev-utils/generated-artifacts/
+contracts/dev-utils/test/generated-artifacts/
+contracts/zero-ex/generated-artifacts/
+contracts/zero-ex/test/generated-artifacts/
+contracts/treasury/generated-artifacts/
+contracts/treasury/test/generated-artifacts/
+
+# generated truffle contract artifacts/
+contracts/broker/build/
+contracts/erc20-bridge-sampler/build/
+contracts/staking/build/
+contracts/coordinator/build/
+contracts/exchange/build/
+contracts/asset-proxy/build/
+contracts/multisig/build/
+contracts/utils/build/
+contracts/exchange-libs/build/
+contracts/erc20/build/
+contracts/erc721/build/
+contracts/erc1155/build/
+contracts/extensions/build/
+contracts/exchange-forwarder/build/
+contracts/dev-utils/build/

 # generated contract wrappers
-packages/abi-gen-wrappers/wrappers
-contracts/protocol/generated-wrappers/
+contracts/broker/generated-wrappers/
+contracts/broker/test/generated-wrappers/
+packages/python-contract-wrappers/generated/
+contracts/erc20-bridge-sampler/generated-wrappers/
+contracts/erc20-bridge-sampler/test/generated-wrappers/
+contracts/integrations/generated-wrappers/
+contracts/integrations/test/generated-wrappers/
+contracts/staking/generated-wrappers/
+contracts/staking/test/generated-wrappers/
+contracts/coordinator/generated-wrappers/
+contracts/coordinator/test/generated-wrappers/
+contracts/exchange/generated-wrappers/
+contracts/exchange/test/generated-wrappers/
+contracts/asset-proxy/generated-wrappers/
+contracts/asset-proxy/test/generated-wrappers/
 contracts/multisig/generated-wrappers/
+contracts/multisig/test/generated-wrappers/
 contracts/utils/generated-wrappers/
-contracts/libs/generated-wrappers/
-contracts/interfaces/generated-wrappers/
-contracts/tokens/generated-wrappers/
-contracts/examples/generated-wrappers/
+contracts/utils/test/generated-wrappers/
+contracts/exchange-libs/generated-wrappers/
+contracts/exchange-libs/test/generated-wrappers/
+contracts/erc20/generated-wrappers/
+contracts/erc20/test/generated-wrappers/
+contracts/erc721/generated-wrappers/
+contracts/erc721/test/generated-wrappers/
+contracts/erc1155/generated-wrappers/
+contracts/erc1155/test/generated-wrappers/
 contracts/extensions/generated-wrappers/
-packages/metacoin/src/contract_wrappers
+contracts/extensions/test/generated-wrappers/
+contracts/exchange-forwarder/generated-wrappers/
+contracts/exchange-forwarder/test/generated-wrappers/
+contracts/dev-utils/generated-wrappers/
+contracts/dev-utils/test/generated-wrappers/
+contracts/zero-ex/generated-wrappers/
+contracts/zero-ex/test/generated-wrappers/
+contracts/treasury/generated-wrappers/
+contracts/treasury/test/generated-wrappers/

-# solc-bin in sol-compiler
-packages/sol-compiler/solc_bin/
+# Doc README copy
+packages/*/docs/README.md

-# Monorepo scripts
-packages/*/scripts/
+.DS_Store

-# python stuff
-.eggs
-.mypy_cache
-.tox
-python-packages/*/build
-python-packages/*/dist
-__pycache__
-python-packages/*/src/*.egg-info
-python-packages/*/.coverage
+# the snapshot that gets built for migrations sure does have a ton of files
+packages/migrations/0x_ganache_snapshot*
--- a/.prettierignore
+++ b/.prettierignore
@@ -1,33 +1,90 @@
 lib
 .nyc_output
-/contracts/protocol/generated-wrappers
-/contracts/protocol/generated-artifacts
+/contracts/broker/generated-wrappers
+/contracts/broker/test/generated-wrappers
+/contracts/broker/generated-artifacts
+/contracts/broker/test/generated-artifacts
+/contracts/integrations/generated-wrappers
+/contracts/integrations/test/generated-wrappers
+/contracts/integrations/generated-artifacts
+/contracts/integrations/test/generated-artifacts
+/contracts/staking/generated-wrappers
+/contracts/staking/test/generated-wrappers
+/contracts/staking/generated-artifacts
+/contracts/staking/test/generated-artifacts
+/contracts/coordinator/generated-wrappers
+/contracts/coordinator/test/generated-wrappers
+/contracts/coordinator/generated-artifacts
+/contracts/coordinator/test/generated-artifacts
+/contracts/exchange/generated-wrappers
+/contracts/exchange/test/generated-wrappers
+/contracts/exchange/generated-artifacts
+/contracts/exchange/test/generated-artifacts
+/contracts/asset-proxy/generated-wrappers
+/contracts/asset-proxy/test/generated-wrappers
+/contracts/asset-proxy/generated-artifacts
+/contracts/asset-proxy/test/generated-artifacts
 /contracts/multisig/generated-wrappers
+/contracts/multisig/test/generated-wrappers
 /contracts/multisig/generated-artifacts
+/contracts/multisig/test/generated-artifacts
 /contracts/utils/generated-wrappers
+/contracts/utils/test/generated-wrappers
 /contracts/utils/generated-artifacts
-/contracts/libs/generated-wrappers
-/contracts/libs/generated-artifacts
-/contracts/interfaces/generated-wrappers
-/contracts/interfaces/generated-artifacts
-/contracts/tokens/generated-wrappers
-/contracts/tokens/generated-artifacts
-/contracts/examples/generated-wrappers
-/contracts/examples/generated-artifacts
+/contracts/utils/test/generated-artifacts
+/contracts/exchange-libs/generated-wrappers
+/contracts/exchange-libs/test/generated-wrappers
+/contracts/exchange-libs/generated-artifacts
+/contracts/exchange-libs/test/generated-artifacts
+/contracts/erc20/generated-wrappers
+/contracts/erc20/test/generated-wrappers
+/contracts/erc20/generated-artifacts
+/contracts/erc20/test/generated-artifacts
+/contracts/erc721/generated-wrappers
+/contracts/erc721/test/generated-wrappers
+/contracts/erc721/generated-artifacts
+/contracts/erc721/test/generated-artifacts
+/contracts/erc1155/generated-wrappers
+/contracts/erc1155/test/generated-wrappers
+/contracts/erc1155/generated-artifacts
+/contracts/erc1155/test/generated-artifacts
 /contracts/extensions/generated-wrappers
+/contracts/extensions/test/generated-wrappers
 /contracts/extensions/generated-artifacts
-/packages/abi-gen-wrappers/src/generated-wrappers
-/packages/contract-artifacts/artifacts
-/python-packages/contract_artifacts/src/zero_ex/contract_artifacts/artifacts
-/packages/json-schemas/schemas
-/python-packages/json_schemas/src/zero_ex/json_schemas/schemas
-/packages/metacoin/src/contract_wrappers
-/packages/metacoin/artifacts
-/packages/sra-spec/public/
-/packages/dev-tools-pages/ts/**/data.json
+/contracts/extensions/test/generated-artifacts
+/contracts/exchange-forwarder/generated-wrappers
+/contracts/exchange-forwarder/test/generated-wrappers
+/contracts/exchange-forwarder/generated-artifacts
+/contracts/exchange-forwarder/test/generated-artifacts
+/contracts/dev-utils/generated-wrappers
+/contracts/dev-utils/test/generated-wrappers
+/contracts/dev-utils/generated-artifacts
+/contracts/dev-utils/test/generated-artifacts
+/contracts/zero-ex/generated-wrappers
+/contracts/zero-ex/test/generated-wrappers
+/contracts/zero-ex/generated-artifacts
+/contracts/zero-ex/test/generated-artifacts
+/contracts/treasury/generated-wrappers
+/contracts/treasury/test/generated-wrappers
+/contracts/treasury/generated-artifacts
+/contracts/treasury/test/generated-artifacts
+/contracts/staking/build/
+/contracts/coordinator/build/
+/contracts/exchange/build/
+/contracts/asset-proxy/build/
+/contracts/multisig/build/
+/contracts/utils/build/
+/contracts/exchange-libs/build/
+/contracts/erc20/build/
+/contracts/erc721/build/
+/contracts/erc1155/build/
+/contracts/extensions/build/
+/contracts/exchange-forwarder/build/
+/packages/asset-swapper/generated-artifacts
+/packages/asset-swapper/generated-wrappers
+/packages/asset-swapper/test/generated-artifacts
+/packages/asset-swapper/test/generated-wrappers
 package.json
-scripts/postpublish_utils.js
-packages/sol-coverage/test/fixtures/artifacts
-.pytest_cache
-.mypy_cache
-.tox
+packages/*/docs
+docs/
+*.sol
--- a/.prettierrc
+++ b/.prettierrc
@@ -1,6 +1,8 @@
 {
-    "tabWidth": 4,
    "printWidth": 120,
-    "trailingComma": all,
-    "singleQuote": true
+    "tabWidth": 4,
+    "singleQuote": true,
+    "trailingComma": "all",
+    "bracketSpacing": true,
+    "arrowParens": "avoid"
 }
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -0,0 +1,23 @@
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: docs/conf.py
+
+# Build documentation with MkDocs
+#mkdocs:
+#  configuration: mkdocs.yml
+
+# Optionally build your docs in additional formats such as PDF
+#formats:
+#  - pdf
+
+# Optionally set the version of Python and requirements required to build your docs
+python:
+  version: 3.7
+  install:
+    - requirements: docs/requirements.txt
--- a/34
+++ b/34
@@ -5,34 +5,14 @@
 # https://git-scm.com/docs/gitignore#_pattern_format

 # Website
-packages/asset-buyer/  @BMillman19 @fragosti @steveklebanoff
-packages/instant/  @BMillman19 @fragosti @steveklebanoff
-packages/website/  @BMillman19 @fragosti @fabioberger @steveklebanoff
+packages/asset-swapper/  @BMillman19 @fragosti @dave4506
+packages/instant/  @BMillman19 @fragosti @dave4506

 # Dev tools & setup
-.circleci/ @LogvinovLeon
-packages/abi-gen/ @LogvinovLeon
-packages/base-contract/ @LogvinovLeon
-packages/connect/ @fragosti 
-packages/abi-gen-templates/ @LogvinovLeon
-packages/contract-addresses/ @albrow
-packages/contract-artifacts/ @albrow
-packages/dev-utils/ @LogvinovLeon @fabioberger
-packages/devnet/ @albrow
-packages/ethereum-types/ @LogvinovLeon
-packages/metacoin/ @LogvinovLeon
-packages/monorepo-scripts/ @fabioberger
-packages/order-utils/ @fabioberger @LogvinovLeon 
-packages/sol-compiler/ @LogvinovLeon
-packages/sol-coverage/ @LogvinovLeon
-packages/sol-profiler/ @LogvinovLeon
-packages/sol-trace/ @LogvinovLeon
-packages/sol-tracing-utils/ @LogvinovLeon
-packages/sol-resolver/ @LogvinovLeon
-packages/subproviders/ @fabioberger @dekz
-packages/verdaccio/ @albrow
-packages/web3-wrapper/ @LogvinovLeon @fabioberger
-python-packages/ @feuGeneA
+.circleci/ @dorothy-zbornak
+packages/contract-addresses/ @abandeali1
+packages/contract-artifacts/ @abandeali1
+packages/order-utils/ @dorothy-zbornak 

 # Protocol/smart contracts
-contracts/core/test/ @albrow
+contracts/ @abandeali1 @hysz @dorothy-zbornak @mzhu25
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -4,9 +4,9 @@ We welcome contributions from anyone on the internet and are grateful for even t

 ### Getting started

-1.  Fork `0xproject/0x-monorepo`
+1.  Fork `0xproject/0x-tools`
 2.  Clone your fork
-3.  Follow the [installation & build steps](https://github.com/0xProject/0x-monorepo#install-dependencies) in the repo's top-level README.
+3.  Follow the [installation & build steps](https://github.com/0xProject/0x-tools#install-dependencies) in the repo's top-level README.
 4.  Setup the recommended [Development Tooling](#development-tooling).
 5.  Open a PR with the `[WIP]` flag against the `development` branch and describe the change you are intending to undertake in the PR description. (see [our branch naming conventions](#branch-structure))

@@ -29,9 +29,9 @@ ALL PRs should be opened against `development`.

 Branch names should be prefixed with `fix`, `feature` or `refactor`.

-   e.g `fix/broken-wiki-link`
+-   e.g `fix/missing-import`
 -   If the PR only edits a single package, add it's name too
-    -   e.g `fix/website/broken-wiki-link`
+    -   e.g `fix/subproviders/missing-import`

 ### CHANGELOGs

@@ -55,15 +55,15 @@ If an entry without a `timestamp` already exists, this means other changes have

 ### Development Tooling

-We strongly recommend you use the [VSCode](https://code.visualstudio.com/) text editor since most of our code is written in Typescript and it offers amazing support for the language.
+We strongly recommend you use the [VSCode](https://code.visualstudio.com/) text editor since most of our code is written in TypeScript and it offers amazing support for the language.

 #### Linter

-We use [TSLint](https://palantir.github.io/tslint/) with [custom configs](https://github.com/0xProject/0x-monorepo/tree/development/packages/tslint-config) to keep our code-style consistent.
+We use [TSLint](https://palantir.github.io/tslint/) with [custom configs](https://github.com/0xProject/0x-tools/tree/development/packages/tslint-config) to keep our code-style consistent.

 Use `yarn:lint` to lint the entire monorepo, and `PKG={PACKAGE_NAME} yarn lint` to lint a specific package.

-If you want to change a rule, or add a custom rule, please make these changes to our [tslint-config](https://github.com/0xProject/0x-monorepo/tree/development/packages/tslint-config) package. All other packages have it as a dependency.
+If you want to change a rule, or add a custom rule, please make these changes to our [tslint-config](https://github.com/0xProject/0x-tools/tree/development/packages/tslint-config) package. All other packages have it as a dependency.

 Integrate it into your text editor:

@@ -89,17 +89,17 @@ A few of our coding conventions are not yet enforced by the linter/auto-formatte
 1.  Do not import from a project's `index.ts` (e.g import { Token } from '../src';). Always import from the source file itself.
 1.  Generic error variables should be named `err` instead of `e` or `error`.
 1.  If you _must_ cast a variable to any - try to type it back as fast as possible. (e.g., `const cw = ((zeroEx as any)._contractWrappers as ContractWrappers);`). This ensures subsequent code is type-safe.
-1.  Our enum conventions coincide with the recommended Typescript conventions, using capitalized keys, and all-caps snake-case values. Eg `GetStats = 'GET_STATS'`
+1.  Our enum conventions coincide with the recommended TypeScript conventions, using capitalized keys, and all-caps snake-case values. Eg `GetStats = 'GET_STATS'`
 1.  All public, exported methods/functions/classes must have associated Javadoc-style comments.

 ### Fix `submit-coverage` CI failure

-If you simply fork the repo and then create a PR from it, your PR will fail the `submit-coverage` check on CI. This is because the 0x CircleCI configuration sets the `COVERALLS_REPO_TOKEN` environment variable to the token for `0xProject/0x-monorepo`, but when running the check against your fork the token needs to match your repo's name `your-username/0x-monorepo`.
+If you simply fork the repo and then create a PR from it, your PR will fail the `submit-coverage` check on CI. This is because the 0x CircleCI configuration sets the `COVERALLS_REPO_TOKEN` environment variable to the token for `0xProject/0x-tools`, but when running the check against your fork the token needs to match your repo's name `your-username/0x-tools`.

 To facilitate this check, after creating your fork, but before creating the branch for your PR, do the following:

 1.  Log in to [coveralls.io](https://coveralls.io/), go to `Add Repos`, and enable your fork. Then go to the settings for that repo, and copy the `Repo Token` identifier.
-2.  Log in to [CircleCI](https://circleci.com/login), go to `Add Projects`, click the `Set Up Project` button corresponding to your fork, and then click `Start Building`. (Aside from step 3 below, no actual set up is needed, since it will use the `.circleci/config.yml` file in 0x-monorepo, so you can ignore all of the instruction/explanation given on the page with the `Start Building` button.)
+2.  Log in to [CircleCI](https://circleci.com/login), go to `Add Projects`, click the `Set Up Project` button corresponding to your fork, and then click `Start Building`. (Aside from step 3 below, no actual set up is needed, since it will use the `.circleci/config.yml` file in 0x-tools, so you can ignore all of the instruction/explanation given on the page with the `Start Building` button.)
 3.  In CircleCI, configure your project to add an environment variable, with name `COVERALLS_REPO_TOKEN`, and for the value paste in the `Repo Token` you copied in step 1.

 Now, when you push to your branch, CircleCI will automatically run all of the checks in your own instance, and the coverage check will work since it has the proper `Repo Token`, and the PR will magically refer to your own checks rather than running them in the 0x CircleCI instance.
--- a/ISSUE_TEMPLATE.md
+++ b/ISSUE_TEMPLATE.md
@@ -2,7 +2,7 @@

 <!--- Before submitting please check to see if this issue was already reported -->

-<!--- Provide a general summary of the issue in the Title above -->
+<!--- Prefix your issue title with the package name it relates to (e.g., `0x.js: ` or `general:`) -->

 ## Expected Behavior

@@ -49,7 +49,6 @@
 | Package | Version |
 | ------: | :------ |

-
 <!-- For example:
 |             `0x.js` | 2.0.4   |
 | `Exchange Contract` | v2      |
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-Copyright 2017 ZeroEx Intl.
+Copyright 2020 ZeroEx Labs

 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
--- a/README.md
+++ b/README.md
@@ -2,96 +2,47 @@

 ---

-[0x][website-url] is an open protocol that facilitates trustless, low friction exchange of Ethereum-based assets. For more information on how it works, check out the [0x protocol specification](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md).
+[0x][website-url] is an open protocol that facilitates trustless, low friction exchange of Ethereum-based assets. For more information on how it works, check out the [0x protocol specification](https://protocol.0x.org/).

 This repository is a monorepo including the 0x protocol smart contracts and numerous developer tools. Each public sub-package is independently published to NPM.

-If you're developing on 0x now or are interested in using 0x infrastructure in the future, please join our [developer mailing list][dev-mailing-list-url] for updates.
+[website-url]: https://0x.org

-[website-url]: https://0xproject.com
-[whitepaper-url]: https://0xproject.com/pdfs/0x_white_paper.pdf
-[dev-mailing-list-url]: http://eepurl.com/dx4cPf
-
-[![CircleCI](https://circleci.com/gh/0xProject/0x-monorepo.svg?style=svg&circle-token=61bf7cd8c9b4e11b132089dfcffdd1be277d1e0c)](https://circleci.com/gh/0xProject/0x-monorepo)
+[![CircleCI](https://circleci.com/gh/0xProject/protocol.svg?style=svg&circle-token=61bf7cd8c9b4e11b132089dfcffdd1be277d1e0c)](https://circleci.com/gh/0xProject/protocool)
 [![Coverage Status](https://coveralls.io/repos/github/0xProject/0x-monorepo/badge.svg?branch=development)](https://coveralls.io/github/0xProject/0x-monorepo?branch=development)
-[![Discord](https://img.shields.io/badge/chat-rocket.chat-yellow.svg?style=flat)](https://chat.0xproject.com)
-[![Join the chat at https://gitter.im/0xProject/Lobby](https://badges.gitter.im/0xProject/Lobby.svg)](https://gitter.im/0xProject/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Discord](https://img.shields.io/badge/chat-discord.chat-yellow.svg?style=flat)](https://discordapp.com/invite/d3FTX3M)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)

 ## Packages

-Visit our [developer portal](https://0xproject.com/docs/order-utils) for a comprehensive list of core & community maintained packages. All packages maintained with this monorepo are listed below.
+Visit our [developer portal](https://0x.org/docs/) for a comprehensive list of core & community maintained packages. All packages maintained with this monorepo are listed below.

-### Python Packages
+### Solidity Packages
+
+These packages are all under development. See [/contracts/README.md](/contracts/README.md) for a list of deployed packages.

 | Package                                             | Version                                                                                                                     | Description                                                          |
-| -------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
-| [`0x-contract-addresses`](/python-packages/contract_addresses) | [![PyPI](https://img.shields.io/pypi/v/0x-contract-addresses.svg)](https://pypi.org/project/0x-contract-addresses/) | A tiny utility library for getting known deployed contract addresses for a particular network     |
-| [`0x-contract-artifacts`](/python-packages/contract_artifacts) | [![PyPI](https://img.shields.io/pypi/v/0x-contract-artifacts.svg)](https://pypi.org/project/0x-contract-artifacts/) | 0x smart contract compilation artifacts                                                           |
-| [`0x-json-schemas`](/python-packages/json_schemas)             | [![PyPI](https://img.shields.io/pypi/v/0x-json-schemas.svg)](https://pypi.org/project/0x-json-schemas/)             | 0x-related JSON schemas                                                                           |
-| [`0x-order-utils`](/python-packages/order_utils)               | [![PyPI](https://img.shields.io/pypi/v/0x-order-utils.svg)](https://pypi.org/project/0x-order-utils/)               | A set of utilities for generating, parsing, signing and validating 0x orders                      |
-| [`0x-sra-client`](/python-packages/sra_client)                 | [![PyPI](https://img.shields.io/pypi/v/0x-sra-client.svg)](https://pypi.org/project/0x-sra-client/)                 | A Python client for interacting with servers conforming to the Standard Relayer API specification |
+| --------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------- |
+| [`@0x/contracts-zero-ex`](/contracts/zero-ex)       | [![npm](https://img.shields.io/npm/v/@0x/contracts-zero-ex.svg)](https://www.npmjs.com/package/@0x/contracts-zero-ex)       | The contracts used for settling trades within the protocol           |
+| [`@0x/contracts-erc20`](/contracts/erc20)           | [![npm](https://img.shields.io/npm/v/@0x/contracts-erc20.svg)](https://www.npmjs.com/package/@0x/contracts-erc20)           | Implementations of various ERC20 tokens                              |
+| [`@0x/contracts-test-utils`](/contracts/test-utils) | [![npm](https://img.shields.io/npm/v/@0x/contracts-test-utils.svg)](https://www.npmjs.com/package/@0x/contracts-test-utils) | TypeScript/Javascript shared utilities used for testing contracts    |
+| [`@0x/contracts-utils`](/contracts/utils)           | [![npm](https://img.shields.io/npm/v/@0x/contracts-utils.svg)](https://www.npmjs.com/package/@0x/contracts-utils)           | Generic libraries and utilities used throughout all of the contracts |

-### Typescript/Javascript Packages
+### TypeScript/Javascript Packages

 #### 0x-specific packages

 | Package                                                  | Version                                                                                                                 | Description                                                                                    |
-| -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
-| [`0x.js`](/packages/0x.js)                               | [![npm](https://img.shields.io/npm/v/0x.js.svg)](https://www.npmjs.com/package/0x.js)                                   | An aggregate package combining many smaller utility packages for interacting with the 0x protocol |
+| -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------- |
+| [`@0x/asset-swapper`](/packages/asset-swapper)           | [![npm](https://img.shields.io/npm/v/@0x/asset-swapper.svg)](https://www.npmjs.com/package/@0x/asset-swapper)           | Package used to find and create aggregated swaps                                               |
+| [`@0x/protocol-utils`](/packages/protocol-utils)         | [![npm](https://img.shields.io/npm/v/@0x/protocol-utils.svg)](https://www.npmjs.com/package/@0x/protocol-utils)         | A set of utilities for generating, parsing, signing and validating 0x orders                   |
 | [`@0x/contract-addresses`](/packages/contract-addresses) | [![npm](https://img.shields.io/npm/v/@0x/contract-addresses.svg)](https://www.npmjs.com/package/@0x/contract-addresses) | A tiny utility library for getting known deployed contract addresses for a particular network. |
 | [`@0x/contract-wrappers`](/packages/contract-wrappers)   | [![npm](https://img.shields.io/npm/v/@0x/contract-wrappers.svg)](https://www.npmjs.com/package/@0x/contract-wrappers)   | JS/TS wrappers for interacting with the 0x smart contracts                                     |
-| [`@0x/order-utils`](/packages/order-utils)               | [![npm](https://img.shields.io/npm/v/@0x/order-utils.svg)](https://www.npmjs.com/package/@0x/order-utils)               | A set of utilities for generating, parsing, signing and validating 0x orders                      |
-| [`@0x/json-schemas`](/packages/json-schemas)             | [![npm](https://img.shields.io/npm/v/@0x/json-schemas.svg)](https://www.npmjs.com/package/@0x/json-schemas)             | 0x-related JSON schemas                                                                           |
-| [`@0x/order-watcher`](/packages/order-watcher)           | [![npm](https://img.shields.io/npm/v/@0x/order-watcher.svg)](https://www.npmjs.com/package/@0x/order-watcher)           | An order watcher daemon that watches for order validity                                           |
-| [`@0x/migrations`](/packages/migrations)                 | [![npm](https://img.shields.io/npm/v/@0x/migrations.svg)](https://www.npmjs.com/package/@0x/migrations)                 | Migration tool for deploying 0x smart contracts on private testnets                               |
-| [`@0x/contract-artifacts`](/packages/contract-artifacts) | [![npm](https://img.shields.io/npm/v/@0x/contract-artifacts.svg)](https://www.npmjs.com/package/@0x/contract-artifacts) | 0x smart contract compilation artifacts                                                           |
-| [`@0x/abi-gen-wrappers`](/packages/abi-gen-wrappers)     | [![npm](https://img.shields.io/npm/v/@0x/abi-gen-wrappers.svg)](https://www.npmjs.com/package/@0x/abi-gen-wrappers)     | Low-level 0x smart contract wrappers generated using `@0x/abi-gen`                                |
-| [`@0x/sra-spec`](/packages/sra-spec)                     | [![npm](https://img.shields.io/npm/v/@0x/sra-spec.svg)](https://www.npmjs.com/package/@0x/sra-spec)                     | OpenAPI specification for the Standard Relayer API                                                |
-| [`@0x/connect`](/packages/connect)                       | [![npm](https://img.shields.io/npm/v/@0x/connect.svg)](https://www.npmjs.com/package/@0x/connect)                       | An HTTP/WS client for interacting with the Standard Relayer API                                   |
-| [`@0x/asset-buyer`](/packages/asset-buyer)               | [![npm](https://img.shields.io/npm/v/@0x/asset-buyer.svg)](https://www.npmjs.com/package/@0x/asset-buyer)               | Convenience package for discovering and buying assets with Ether                                  |
-
-#### Ethereum tooling
-
-| Package                                      | Version                                                                                                     | Description                                                                                                                                                                             |
-| -------------------------------------------- | ----------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| [`@0x/web3-wrapper`](/packages/web3-wrapper) | [![npm](https://img.shields.io/npm/v/@0x/web3-wrapper.svg)](https://www.npmjs.com/package/@0x/web3-wrapper) | An Ethereum JSON RPC client                                                                                                                                                             |
-| [`@0x/sol-compiler`](/packages/sol-compiler) | [![npm](https://img.shields.io/npm/v/@0x/sol-compiler.svg)](https://www.npmjs.com/package/@0x/sol-compiler) | A wrapper around solc-js that adds smart re-compilation, ability to compile an entire project, Solidity version specific compilation, standard input description support and much more. |
-| [`@0x/sol-coverage`](/packages/sol-coverage) | [![npm](https://img.shields.io/npm/v/@0x/sol-coverage.svg)](https://www.npmjs.com/package/@0x/sol-coverage) | A solidity test coverage tool                                                                                                                                                           |
-| [`@0x/sol-profiler`](/packages/sol-profiler) | [![npm](https://img.shields.io/npm/v/@0x/sol-profiler.svg)](https://www.npmjs.com/package/@0x/sol-profiler) | A solidity gas cost profiler                                                                                                                                                            |
-| [`@0x/sol-trace`](/packages/sol-trace)       | [![npm](https://img.shields.io/npm/v/@0x/sol-trace.svg)](https://www.npmjs.com/package/@0x/sol-trace)       | A solidity stack trace tool                                                                                                                                                             |
-| [`@0x/sol-resolver`](/packages/sol-resolver) | [![npm](https://img.shields.io/npm/v/@0x/sol-resolver.svg)](https://www.npmjs.com/package/@0x/sol-resolver) | Import resolver for smart contracts dependencies                                                                                                                                        |
-| [`@0x/subproviders`](/packages/subproviders) | [![npm](https://img.shields.io/npm/v/@0x/subproviders.svg)](https://www.npmjs.com/package/@0x/subproviders) | Web3 provider middlewares (e.g. LedgerSubprovider)                                                                                                                                      |
-| [`@0x/sol-doc`](/packages/sol-doc)           | [![npm](https://img.shields.io/npm/v/@0x/sol-doc.svg)](https://www.npmjs.com/package/@0x/sol-doc)           | Solidity documentation generator                                                                                                                                                        |
-
-#### Utilities
-
-| Package                                                  | Version                                                                                                                 | Description                                                                  |
-| -------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------- |
-| [`@0x/abi-gen`](/packages/abi-gen)                       | [![npm](https://img.shields.io/npm/v/@0x/abi-gen.svg)](https://www.npmjs.com/package/@0x/abi-gen)                       | Tool to generate TS wrappers from smart contract ABIs                        |
-| [`@0x/tslint-config`](/packages/tslint-config)           | [![npm](https://img.shields.io/npm/v/@0x/tslint-config.svg)](https://www.npmjs.com/package/@0x/tslint-config)           | Custom TSLint rules used by the 0x core team                                 |
-| [`@0x/types`](/packages/types)                           | [![npm](https://img.shields.io/npm/v/@0x/types.svg)](https://www.npmjs.com/package/@0x/types)                           | Shared type declarations                                                     |
-| [`@0x/typescript-typings`](/packages/typescript-typings) | [![npm](https://img.shields.io/npm/v/@0x/typescript-typings.svg)](https://www.npmjs.com/package/@0x/typescript-typings) | Repository of types for external packages                                    |
-| [`@0x/utils`](/packages/utils)                           | [![npm](https://img.shields.io/npm/v/@0x/utils.svg)](https://www.npmjs.com/package/@0x/utils)                           | Shared utilities                                                             |
-| [`@0x/react-docs`](/packages/react-docs)                 | [![npm](https://img.shields.io/npm/v/@0x/react-docs.svg)](https://www.npmjs.com/package/@0x/react-docs)                 | React documentation component for rendering TypeDoc & sol-doc generated JSON |
-| [`@0x/react-shared`](/packages/react-shared)             | [![npm](https://img.shields.io/npm/v/@0x/react-shared.svg)](https://www.npmjs.com/package/@0x/react-shared)             | 0x shared react components                                                   |
-| [`@0x/assert`](/packages/assert)                         | [![npm](https://img.shields.io/npm/v/@0x/assert.svg)](https://www.npmjs.com/package/@0x/assert)                         | Type and schema assertions used by our packages                              |
-| [`@0x/base-contract`](/packages/base-contract)           | [![npm](https://img.shields.io/npm/v/@0x/base-contract.svg)](https://www.npmjs.com/package/@0x/base-contract)           | BaseContract used by auto-generated `abi-gen` wrapper contracts              |
-| [`@0x/dev-utils`](/packages/dev-utils)                   | [![npm](https://img.shields.io/npm/v/@0x/dev-utils.svg)](https://www.npmjs.com/package/@0x/dev-utils)                   | Dev utils to be shared across 0x packages                                    |
-| [`@0x/fill-scenarios`](/packages/fill-scenarios)         | [![npm](https://img.shields.io/npm/v/@0x/fill-scenarios.svg)](https://www.npmjs.com/package/@0x/fill-scenarios)         | 0x order fill scenario generator                                             |
-
-#### Private Packages
-
-| Package                                            | Description                                                                      |
-| -------------------------------------------------- | -------------------------------------------------------------------------------- |
-| [`@0x/contracts`](/contracts/core)                 | 0x protocol solidity smart contracts & tests                                     |
-| [`@0x/instant`](/packages/instant)                 | A free and flexible way to offer simple crypto purchasing in any app or website. |
-| [`@0x/testnet-faucets`](/packages/testnet-faucets) | A faucet micro-service that dispenses test ERC20 tokens or Ether                 |
-| [`@0x/website`](/packages/website)                 | 0x website                                                                       |
+| [`@0x/contract-artifacts`](/packages/contract-artifacts) | [![npm](https://img.shields.io/npm/v/@0x/contract-artifacts.svg)](https://www.npmjs.com/package/@0x/contract-artifacts) | 0x smart contract compilation artifacts                                                        |  |

 ## Usage

-Node version >= 6.12 is required.
+Node version 6.x or 8.x is required.

 Most of the packages require additional typings for external dependencies.
 You can include those by prepending the `@0x/typescript-typings` package to your [`typeRoots`](http://www.typescriptlang.org/docs/handbook/tsconfig-json.html) config.
@@ -131,7 +82,13 @@ yarn build
 To build a specific package:

 ```bash
-PKG=@0x/web3-wrapper yarn build
+PKG=@0x/asset-swapper yarn build
+```
+
+To build all contracts packages:
+
+```bash
+yarn build:contracts
 ```

 ### Watch
@@ -148,7 +105,7 @@ To watch a specific package and all it's dependent packages:
 PKG=[NPM_PACKAGE_NAME] yarn watch

 e.g
-PKG=@0x/web3-wrapper yarn watch
+PKG=@0x/asset-swapper yarn watch
 ```

 ### Clean
@@ -162,7 +119,7 @@ yarn clean
 Clean a specific package

 ```bash
-PKG=0x.js yarn clean
+PKG=@0x/asset-swapper yarn clean
 ```

 ### Rebuild
@@ -176,7 +133,7 @@ yarn rebuild
 To re-build (clean & build) a specific package & it's deps:

 ```bash
-PKG=0x.js yarn rebuild
+PKG=@0x/asset-swapper yarn rebuild
 ```

 ### Lint
@@ -190,7 +147,7 @@ yarn lint
 Lint a specific package:

 ```bash
-PKG=0x.js yarn lint
+PKG=@0x/asset-swapper yarn lint
 ```

 ### Run Tests
@@ -204,5 +161,11 @@ yarn test
 Run a specific package's test:

 ```bash
-PKG=@0x/web3-wrapper yarn test
+PKG=@0x/asset-swapper yarn test
+```
+
+Run all contracts packages tests:
+
+```bash
+yarn test:contracts
 ```
--- a/contracts/.solhint.json
+++ b/contracts/.solhint.json
@@ -16,6 +16,7 @@
        "quotes": ["error", "double"],
        "separate-by-one-line-in-contract": "error",
        "space-after-comma": "error",
-        "statement-indent": "error"
+        "statement-indent": "error",
+        "no-empty-blocks": false
    }
 }
--- a/contracts/README.md
+++ b/contracts/README.md
@@ -0,0 +1,3 @@
+#### Development
+
+Building solidity files will update the contract artifact in `{package-name}/generated-artifacts/{contract}.json`, but does not automatically update the `contract-artifacts` or `contract-wrappers` packages, which are generated from the artifact JSON. See `contract-artifacts/README.md` for instructions on updating these packages.
--- a/contracts/TESTING.md
+++ b/contracts/TESTING.md
@@ -1,48 +0,0 @@
-# Contracts testing options
-
-## Revert stack traces
-
-If you want to see helpful stack traces (incl. line number, code snippet) for smart contract reverts, run the tests with:
-
-```
-yarn test:trace
-```
-
-**Note:** This currently slows down the test runs and is therefore not enabled by default.
-
-## Backing Ethereum node
-
-By default, our tests run against an in-process [Ganache](https://github.com/trufflesuite/ganache-core) instance. In order to run the tests against [Geth](https://github.com/ethereum/go-ethereum), first follow the instructions in the README for the devnet package to start the devnet Geth node. Then run:
-
-```bash
-TEST_PROVIDER=geth yarn test
-```
-
-## Code coverage
-
-In order to see the Solidity code coverage output generated by `@0x/sol-coverage`, run:
-
-```
-yarn test:coverage
-```
-
-## Gas profiler
-
-In order to profile the gas costs for a specific smart contract call/transaction, you can run the tests in `profiler` mode.
-
-**Note:** Traces emitted by ganache have incorrect gas costs so we recommend using Geth for profiling.
-
-```
-TEST_PROVIDER=geth yarn test:profiler
-```
-
-You'll see a warning that you need to explicitly enable and disable the profiler before and after the block of code you want to profile.
-
-```typescript
-import { profiler } from './utils/profiler';
-profiler.start();
-// Some call to a smart contract
-profiler.stop();
-```
-
-Without explicitly starting and stopping the profiler, the profiler output will be too busy, and therefore unusable.
--- a/contracts/erc20/.npmignore
+++ b/contracts/erc20/.npmignore
@@ -0,0 +1,10 @@
+# Blacklist all files
+.*
+*
+# Whitelist lib
+!lib/**/*
+# Whitelist Solidity contracts
+!contracts/src/**/*
+# Blacklist tests in lib
+/lib/test/*
+# Package specific ignore
--- a/contracts/erc20/.solhintignore
+++ b/contracts/erc20/.solhintignore
@@ -0,0 +1 @@
+contracts/src/ZRXToken.sol
--- a/contracts/erc20/CHANGELOG.json
+++ b/contracts/erc20/CHANGELOG.json
@@ -0,0 +1,868 @@
+[
+    {
+        "timestamp": 1654284040,
+        "version": "3.3.31",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1652919697,
+        "version": "3.3.30",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1650611093,
+        "version": "3.3.29",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1648739346,
+        "version": "3.3.28",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1646225739,
+        "version": "3.3.27",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1645569128,
+        "version": "3.3.26",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1640364306,
+        "version": "3.3.25",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1638390144,
+        "version": "3.3.24",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1637102971,
+        "version": "3.3.23",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1635903615,
+        "version": "3.3.22",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1634668033,
+        "version": "3.3.21",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1631710679,
+        "version": "3.3.20",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1631120757,
+        "version": "3.3.19",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1630459879,
+        "version": "3.3.18",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1629353596,
+        "version": "3.3.17",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1629079369,
+        "version": "3.3.16",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "3.3.15",
+        "changes": [
+            {
+                "note": "Add ethers as a dependency",
+                "pr": 305
+            }
+        ],
+        "timestamp": 1628665757
+    },
+    {
+        "timestamp": 1628225642,
+        "version": "3.3.14",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1624356181,
+        "version": "3.3.13",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "3.3.12",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1622609597,
+        "version": "3.3.11",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1621944788,
+        "version": "3.3.10",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1621600614,
+        "version": "3.3.9",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1620214333,
+        "version": "3.3.8",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1619596077,
+        "version": "3.3.7",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1617311315,
+        "version": "3.3.6",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1616005394,
+        "version": "3.3.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1614141718,
+        "version": "3.3.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1612950500,
+        "version": "3.3.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1611648096,
+        "version": "3.3.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1610510890,
+        "version": "3.3.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "3.3.0",
+        "changes": [
+            {
+                "note": "Add SPDX license identifiers to solidity files",
+                "pr": 105
+            },
+            {
+                "note": "Allow for excess return data in `LibERC20TokenV06` compat* functions",
+                "pr": 97
+            }
+        ],
+        "timestamp": 1609802516
+    },
+    {
+        "timestamp": 1608692071,
+        "version": "3.2.14",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1608245516,
+        "version": "3.2.13",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1607485227,
+        "version": "3.2.12",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1607381756,
+        "version": "3.2.11",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1606961263,
+        "version": "3.2.10",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1605763885,
+        "version": "3.2.9",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1605302002,
+        "version": "3.2.8",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1604385937,
+        "version": "3.2.7",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1604376968,
+        "version": "3.2.6",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1604355662,
+        "version": "3.2.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1603851023,
+        "version": "3.2.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1603833198,
+        "version": "3.2.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1603265572,
+        "version": "3.2.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1594788383,
+        "version": "3.2.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "3.2.0",
+        "changes": [
+            {
+                "note": "Add `LibERC20Token.approveIfBelow()`",
+                "pr": 2512
+            },
+            {
+                "note": "Add solidity 0.6 contracts",
+                "pr": 2545
+            },
+            {
+                "note": "Update `LibERC20TokenV06` comments.",
+                "pr": 2597
+            }
+        ],
+        "timestamp": 1592969527
+    },
+    {
+        "timestamp": 1583220306,
+        "version": "3.1.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1582837861,
+        "version": "3.1.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1582677073,
+        "version": "3.1.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1582623685,
+        "version": "3.1.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1581748629,
+        "version": "3.1.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "3.1.0",
+        "changes": [
+            {
+                "note": "Add `allowance()` and `balanceOf()` to `LibERC20Token`",
+                "pr": 2464
+            },
+            {
+                "note": "Fix broken tests",
+                "pr": 2456
+            }
+        ],
+        "timestamp": 1581204851
+    },
+    {
+        "timestamp": 1580988106,
+        "version": "3.0.6",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1580811564,
+        "version": "3.0.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1579682890,
+        "version": "3.0.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1578272714,
+        "version": "3.0.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1576540892,
+        "version": "3.0.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1575931811,
+        "version": "3.0.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "3.0.0",
+        "changes": [
+            {
+                "note": "Drastically reduced bundle size by adding .npmignore, only exporting specific artifacts/wrappers/utils",
+                "pr": 2330
+            },
+            {
+                "note": "Add `decimals()` to `LibERC20Token`.",
+                "pr": 2344
+            },
+            {
+                "note": "Create `LibERC20Token`",
+                "pr": 2309
+            },
+            {
+                "note": "Replaced `SafeMath` with `LibSafeMath`",
+                "pr": 2254
+            }
+        ],
+        "timestamp": 1575296764
+    },
+    {
+        "version": "2.3.0-beta.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ],
+        "timestamp": 1575290197
+    },
+    {
+        "version": "2.3.0-beta.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ],
+        "timestamp": 1574238768
+    },
+    {
+        "version": "2.3.0-beta.2",
+        "changes": [
+            {
+                "note": "Drastically reduced bundle size by adding .npmignore, only exporting specific artifacts/wrappers/utils",
+                "pr": 2330
+            },
+            {
+                "note": "Add `decimals()` to `LibERC20Token`.",
+                "pr": 2344
+            }
+        ],
+        "timestamp": 1574030254
+    },
+    {
+        "version": "2.3.0-beta.1",
+        "changes": [
+            {
+                "note": "Create `LibERC20Token`",
+                "pr": 2309
+            }
+        ],
+        "timestamp": 1573159180
+    },
+    {
+        "version": "2.3.0-beta.0",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            },
+            {
+                "note": "Replaced `SafeMath` with `LibSafeMath`",
+                "pr": 2254
+            }
+        ],
+        "timestamp": 1570135330
+    },
+    {
+        "timestamp": 1568744790,
+        "version": "2.2.14",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1567521715,
+        "version": "2.2.13",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1566446343,
+        "version": "2.2.12",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1565296576,
+        "version": "2.2.11",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "2.2.10",
+        "changes": [
+            {
+                "note": "Updated calls to <contract wrapper>.deployFrom0xArtifactAsync to include artifact dependencies.",
+                "pr": 1995
+            }
+        ],
+        "timestamp": 1564604963
+    },
+    {
+        "timestamp": 1563957393,
+        "version": "2.2.9",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1563193019,
+        "version": "2.2.8",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1563047529,
+        "version": "2.2.7",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1563006338,
+        "version": "2.2.6",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1558712885,
+        "version": "2.2.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1557961111,
+        "version": "2.2.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "2.2.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ],
+        "timestamp": 1557799313
+    },
+    {
+        "timestamp": 1557507213,
+        "version": "2.2.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "2.2.0",
+        "changes": [
+            {
+                "note": "Added UntransferrableDummyERC20Token",
+                "pr": 1714
+            }
+        ],
+        "timestamp": 1554997931
+    },
+    {
+        "version": "2.1.0",
+        "changes": [
+            {
+                "note": "Run Web3ProviderEngine without excess block polling",
+                "pr": 1695
+            }
+        ],
+        "timestamp": 1553183790
+    },
+    {
+        "version": "2.0.0",
+        "changes": [
+            {
+                "note": "Upgrade contracts to Solidity 0.5.5",
+                "pr": 1682
+            }
+        ],
+        "timestamp": 1553091633
+    },
+    {
+        "timestamp": 1551479279,
+        "version": "1.0.9",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1551299797,
+        "version": "1.0.8",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1551220833,
+        "version": "1.0.7",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1551130135,
+        "version": "1.0.6",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1549733923,
+        "version": "1.0.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "1.0.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ],
+        "timestamp": 1549547375
+    },
+    {
+        "version": "1.0.3",
+        "changes": [
+            {
+                "note": "Fake publish to enable pinning"
+            }
+        ],
+        "timestamp": 1549504360
+    },
+    {
+        "timestamp": 1549452781,
+        "version": "1.0.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1549373905,
+        "version": "1.0.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "Move all ERC20 contracts out of contracts-tokens to new package",
+                "pr": 1539
+            }
+        ]
+    }
+]
--- a/contracts/erc20/CHANGELOG.md
+++ b/contracts/erc20/CHANGELOG.md
@@ -0,0 +1,379 @@
+<!--
+changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
+Edit the package's CHANGELOG.json file only.
+-->
+
+CHANGELOG
+
+## v3.3.31 - _June 3, 2022_
+
+    * Dependencies updated
+
+## v3.3.30 - _May 19, 2022_
+
+    * Dependencies updated
+
+## v3.3.29 - _April 22, 2022_
+
+    * Dependencies updated
+
+## v3.3.28 - _March 31, 2022_
+
+    * Dependencies updated
+
+## v3.3.27 - _March 2, 2022_
+
+    * Dependencies updated
+
+## v3.3.26 - _February 22, 2022_
+
+    * Dependencies updated
+
+## v3.3.25 - _December 24, 2021_
+
+    * Dependencies updated
+
+## v3.3.24 - _December 1, 2021_
+
+    * Dependencies updated
+
+## v3.3.23 - _November 16, 2021_
+
+    * Dependencies updated
+
+## v3.3.22 - _November 3, 2021_
+
+    * Dependencies updated
+
+## v3.3.21 - _October 19, 2021_
+
+    * Dependencies updated
+
+## v3.3.20 - _September 15, 2021_
+
+    * Dependencies updated
+
+## v3.3.19 - _September 8, 2021_
+
+    * Dependencies updated
+
+## v3.3.18 - _September 1, 2021_
+
+    * Dependencies updated
+
+## v3.3.17 - _August 19, 2021_
+
+    * Dependencies updated
+
+## v3.3.16 - _August 16, 2021_
+
+    * Dependencies updated
+
+## v3.3.15 - _August 11, 2021_
+
+    * Add ethers as a dependency (#305)
+
+## v3.3.14 - _August 6, 2021_
+
+    * Dependencies updated
+
+## v3.3.13 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.3.12 - _June 11, 2021_
+
+    * Dependencies updated
+
+## v3.3.11 - _June 2, 2021_
+
+    * Dependencies updated
+
+## v3.3.10 - _May 25, 2021_
+
+    * Dependencies updated
+
+## v3.3.9 - _May 21, 2021_
+
+    * Dependencies updated
+
+## v3.3.8 - _May 5, 2021_
+
+    * Dependencies updated
+
+## v3.3.7 - _April 28, 2021_
+
+    * Dependencies updated
+
+## v3.3.6 - _April 1, 2021_
+
+    * Dependencies updated
+
+## v3.3.5 - _March 17, 2021_
+
+    * Dependencies updated
+
+## v3.3.4 - _February 24, 2021_
+
+    * Dependencies updated
+
+## v3.3.3 - _February 10, 2021_
+
+    * Dependencies updated
+
+## v3.3.2 - _January 26, 2021_
+
+    * Dependencies updated
+
+## v3.3.1 - _January 13, 2021_
+
+    * Dependencies updated
+
+## v3.3.0 - _January 4, 2021_
+
+    * Add SPDX license identifiers to solidity files (#105)
+    * Allow for excess return data in `LibERC20TokenV06` compat* functions (#97)
+
+## v3.2.14 - _December 23, 2020_
+
+    * Dependencies updated
+
+## v3.2.13 - _December 17, 2020_
+
+    * Dependencies updated
+
+## v3.2.12 - _December 9, 2020_
+
+    * Dependencies updated
+
+## v3.2.11 - _December 7, 2020_
+
+    * Dependencies updated
+
+## v3.2.10 - _December 3, 2020_
+
+    * Dependencies updated
+
+## v3.2.9 - _November 19, 2020_
+
+    * Dependencies updated
+
+## v3.2.8 - _November 13, 2020_
+
+    * Dependencies updated
+
+## v3.2.7 - _November 3, 2020_
+
+    * Dependencies updated
+
+## v3.2.6 - _November 3, 2020_
+
+    * Dependencies updated
+
+## v3.2.5 - _November 2, 2020_
+
+    * Dependencies updated
+
+## v3.2.4 - _October 28, 2020_
+
+    * Dependencies updated
+
+## v3.2.3 - _October 27, 2020_
+
+    * Dependencies updated
+
+## v3.2.2 - _October 21, 2020_
+
+    * Dependencies updated
+
+## v3.2.1 - _July 15, 2020_
+
+    * Dependencies updated
+
+## v3.2.0 - _June 24, 2020_
+
+    * Add `LibERC20Token.approveIfBelow()` (#2512)
+    * Add solidity 0.6 contracts (#2545)
+    * Update `LibERC20TokenV06` comments. (#2597)
+
+## v3.1.5 - _March 3, 2020_
+
+    * Dependencies updated
+
+## v3.1.4 - _February 27, 2020_
+
+    * Dependencies updated
+
+## v3.1.3 - _February 26, 2020_
+
+    * Dependencies updated
+
+## v3.1.2 - _February 25, 2020_
+
+    * Dependencies updated
+
+## v3.1.1 - _February 15, 2020_
+
+    * Dependencies updated
+
+## v3.1.0 - _February 8, 2020_
+
+    * Add `allowance()` and `balanceOf()` to `LibERC20Token` (#2464)
+    * Fix broken tests (#2456)
+
+## v3.0.6 - _February 6, 2020_
+
+    * Dependencies updated
+
+## v3.0.5 - _February 4, 2020_
+
+    * Dependencies updated
+
+## v3.0.4 - _January 22, 2020_
+
+    * Dependencies updated
+
+## v3.0.3 - _January 6, 2020_
+
+    * Dependencies updated
+
+## v3.0.2 - _December 17, 2019_
+
+    * Dependencies updated
+
+## v3.0.1 - _December 9, 2019_
+
+    * Dependencies updated
+
+## v3.0.0 - _December 2, 2019_
+
+    * Drastically reduced bundle size by adding .npmignore, only exporting specific artifacts/wrappers/utils (#2330)
+    * Add `decimals()` to `LibERC20Token`. (#2344)
+    * Create `LibERC20Token` (#2309)
+    * Replaced `SafeMath` with `LibSafeMath` (#2254)
+
+## v2.3.0-beta.4 - _December 2, 2019_
+
+    * Dependencies updated
+
+## v2.3.0-beta.3 - _November 20, 2019_
+
+    * Dependencies updated
+
+## v2.3.0-beta.2 - _November 17, 2019_
+
+    * Drastically reduced bundle size by adding .npmignore, only exporting specific artifacts/wrappers/utils (#2330)
+    * Add `decimals()` to `LibERC20Token`. (#2344)
+
+## v2.3.0-beta.1 - _November 7, 2019_
+
+    * Create `LibERC20Token` (#2309)
+
+## v2.3.0-beta.0 - _October 3, 2019_
+
+    * Dependencies updated
+    * Replaced `SafeMath` with `LibSafeMath` (#2254)
+
+## v2.2.14 - _September 17, 2019_
+
+    * Dependencies updated
+
+## v2.2.13 - _September 3, 2019_
+
+    * Dependencies updated
+
+## v2.2.12 - _August 22, 2019_
+
+    * Dependencies updated
+
+## v2.2.11 - _August 8, 2019_
+
+    * Dependencies updated
+
+## v2.2.10 - _July 31, 2019_
+
+    * Updated calls to <contract wrapper>.deployFrom0xArtifactAsync to include artifact dependencies. (#1995)
+
+## v2.2.9 - _July 24, 2019_
+
+    * Dependencies updated
+
+## v2.2.8 - _July 15, 2019_
+
+    * Dependencies updated
+
+## v2.2.7 - _July 13, 2019_
+
+    * Dependencies updated
+
+## v2.2.6 - _July 13, 2019_
+
+    * Dependencies updated
+
+## v2.2.5 - _May 24, 2019_
+
+    * Dependencies updated
+
+## v2.2.4 - _May 15, 2019_
+
+    * Dependencies updated
+
+## v2.2.3 - _May 14, 2019_
+
+    * Dependencies updated
+
+## v2.2.1 - _May 10, 2019_
+
+    * Dependencies updated
+
+## v2.2.0 - _April 11, 2019_
+
+    * Added UntransferrableDummyERC20Token (#1714)
+
+## v2.1.0 - _March 21, 2019_
+
+    * Run Web3ProviderEngine without excess block polling (#1695)
+
+## v2.0.0 - _March 20, 2019_
+
+    * Upgrade contracts to Solidity 0.5.5 (#1682)
+
+## v1.0.9 - _March 1, 2019_
+
+    * Dependencies updated
+
+## v1.0.8 - _February 27, 2019_
+
+    * Dependencies updated
+
+## v1.0.7 - _February 26, 2019_
+
+    * Dependencies updated
+
+## v1.0.6 - _February 25, 2019_
+
+    * Dependencies updated
+
+## v1.0.5 - _February 9, 2019_
+
+    * Dependencies updated
+
+## v1.0.4 - _February 7, 2019_
+
+    * Dependencies updated
+
+## v1.0.3 - _February 7, 2019_
+
+    * Fake publish to enable pinning
+
+## v1.0.2 - _February 6, 2019_
+
+    * Dependencies updated
+
+## v1.0.1 - _February 5, 2019_
+
+    * Dependencies updated
+
+## v1.0.0 - _Invalid date_
+
+    * Move all ERC20 contracts out of contracts-tokens to new package (#1539)
--- a/contracts/erc20/DEPLOYS.json
+++ b/contracts/erc20/DEPLOYS.json
@@ -0,0 +1,17 @@
+[
+    {
+        "name": "ZRXToken",
+        "version": "1.0.0",
+        "changes": [
+            {
+                "note": "protocol v1 deploy",
+                "networks": {
+                    "1": "0xe41d2489571d322189246dafa5ebde1f4699f498",
+                    "3": "0xff67881f8d12f372d91baae9752eb3631ff0ed00",
+                    "4": "0x2727e688b8fd40b198cd5fe6e408e00494a06f07",
+                    "42": "0x2002d3812f58e35f0ea1ffbf80a75a38c32175fa"
+                }
+            }
+        ]
+    }
+]
--- a/contracts/erc20/README.md
+++ b/contracts/erc20/README.md
@@ -0,0 +1,73 @@
+## ERC20 Tokens
+
+This package contains implementations of various [ERC20](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md) tokens, including WETH (Wrapped Ether) and ZRX. Addresses of the deployed contracts can be found in this 0x [guide](https://0x.org/docs/guides/0x-cheat-sheet) or the [DEPLOYS](./DEPLOYS.json) file within this package.
+
+## Installation
+
+**Install**
+
+```bash
+npm install @0x/contracts-erc20 --save
+```
+
+## Bug bounty
+
+A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0x.org/docs/guides/bug-bounty-program).
+
+## Contributing
+
+We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
+
+For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
+
+Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
+
+### Install Dependencies
+
+If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
+
+```bash
+yarn config set workspaces-experimental true
+```
+
+Then install dependencies
+
+```bash
+yarn install
+```
+
+### Build
+
+To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
+
+```bash
+PKG=@0x/contracts-erc20 yarn build
+```
+
+Or continuously rebuild on change:
+
+```bash
+PKG=@0x/contracts-erc20 yarn watch
+```
+
+### Clean
+
+```bash
+yarn clean
+```
+
+### Lint
+
+```bash
+yarn lint
+```
+
+### Run Tests
+
+```bash
+yarn test
+```
+
+#### Testing options
+
+Contracts testing options like coverage, profiling, revert traces or backing node choosing - are described [here](../TESTING.md).
--- a/contracts/erc20/compiler.json
+++ b/contracts/erc20/compiler.json
@@ -0,0 +1,28 @@
+{
+    "artifactsDir": "./test/generated-artifacts",
+    "contractsDir": "./contracts",
+    "useDockerisedSolc": false,
+    "isOfflineMode": false,
+    "shouldSaveStandardInput": true,
+    "compilerSettings": {
+        "evmVersion": "istanbul",
+        "optimizer": {
+            "enabled": true,
+            "runs": 1000000,
+            "details": { "yul": true, "deduplicate": true, "cse": true, "constantOptimizer": true }
+        },
+        "outputSelection": {
+            "*": {
+                "*": [
+                    "abi",
+                    "devdoc",
+                    "evm.bytecode.object",
+                    "evm.bytecode.sourceMap",
+                    "evm.deployedBytecode.object",
+                    "evm.deployedBytecode.sourceMap",
+                    "devdoc"
+                ]
+            }
+        }
+    }
+}
--- a/contracts/tokens/contracts/tokens/ERC20Token/ERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/ERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,9 +16,9 @@

 */

-pragma solidity ^0.4.24;
+pragma solidity ^0.5.9;

-import "./IERC20Token.sol";
+import "./interfaces/IERC20Token.sol";


 contract ERC20Token is
--- a/contracts/erc20/contracts/src/LibERC20Token.sol
+++ b/contracts/erc20/contracts/src/LibERC20Token.sol
@@ -0,0 +1,199 @@
+/*
+
+  Copyright 2019 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.5.9;
+
+import "@0x/contracts-utils/contracts/src/LibRichErrors.sol";
+import "@0x/contracts-utils/contracts/src/LibBytes.sol";
+import "../src/interfaces/IERC20Token.sol";
+
+
+library LibERC20Token {
+    bytes constant private DECIMALS_CALL_DATA = hex"313ce567";
+
+    /// @dev Calls `IERC20Token(token).approve()`.
+    ///      Reverts if `false` is returned or if the return
+    ///      data length is nonzero and not 32 bytes.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param allowance The allowance to set.
+    function approve(
+        address token,
+        address spender,
+        uint256 allowance
+    )
+        internal
+    {
+        bytes memory callData = abi.encodeWithSelector(
+            IERC20Token(0).approve.selector,
+            spender,
+            allowance
+        );
+        _callWithOptionalBooleanResult(token, callData);
+    }
+
+    /// @dev Calls `IERC20Token(token).approve()` and sets the allowance to the
+    ///      maximum if the current approval is not already >= an amount.
+    ///      Reverts if `false` is returned or if the return
+    ///      data length is nonzero and not 32 bytes.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param amount The minimum allowance needed.
+    function approveIfBelow(
+        address token,
+        address spender,
+        uint256 amount
+    )
+        internal
+    {
+        if (IERC20Token(token).allowance(address(this), spender) < amount) {
+            approve(token, spender, uint256(-1));
+        }
+    }
+
+    /// @dev Calls `IERC20Token(token).transfer()`.
+    ///      Reverts if `false` is returned or if the return
+    ///      data length is nonzero and not 32 bytes.
+    /// @param token The address of the token contract.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function transfer(
+        address token,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        bytes memory callData = abi.encodeWithSelector(
+            IERC20Token(0).transfer.selector,
+            to,
+            amount
+        );
+        _callWithOptionalBooleanResult(token, callData);
+    }
+
+    /// @dev Calls `IERC20Token(token).transferFrom()`.
+    ///      Reverts if `false` is returned or if the return
+    ///      data length is nonzero and not 32 bytes.
+    /// @param token The address of the token contract.
+    /// @param from The owner of the tokens.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function transferFrom(
+        address token,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        bytes memory callData = abi.encodeWithSelector(
+            IERC20Token(0).transferFrom.selector,
+            from,
+            to,
+            amount
+        );
+        _callWithOptionalBooleanResult(token, callData);
+    }
+
+    /// @dev Retrieves the number of decimals for a token.
+    ///      Returns `18` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @return tokenDecimals The number of decimals places for the token.
+    function decimals(address token)
+        internal
+        view
+        returns (uint8 tokenDecimals)
+    {
+        tokenDecimals = 18;
+        (bool didSucceed, bytes memory resultData) = token.staticcall(DECIMALS_CALL_DATA);
+        if (didSucceed && resultData.length == 32) {
+            tokenDecimals = uint8(LibBytes.readUint256(resultData, 0));
+        }
+    }
+
+    /// @dev Retrieves the allowance for a token, owner, and spender.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @param spender The address the spender.
+    /// @return allowance The allowance for a token, owner, and spender.
+    function allowance(address token, address owner, address spender)
+        internal
+        view
+        returns (uint256 allowance_)
+    {
+        (bool didSucceed, bytes memory resultData) = token.staticcall(
+            abi.encodeWithSelector(
+                IERC20Token(0).allowance.selector,
+                owner,
+                spender
+            )
+        );
+        if (didSucceed && resultData.length == 32) {
+            allowance_ = LibBytes.readUint256(resultData, 0);
+        }
+    }
+
+    /// @dev Retrieves the balance for a token owner.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @return balance The token balance of an owner.
+    function balanceOf(address token, address owner)
+        internal
+        view
+        returns (uint256 balance)
+    {
+        (bool didSucceed, bytes memory resultData) = token.staticcall(
+            abi.encodeWithSelector(
+                IERC20Token(0).balanceOf.selector,
+                owner
+            )
+        );
+        if (didSucceed && resultData.length == 32) {
+            balance = LibBytes.readUint256(resultData, 0);
+        }
+    }
+
+    /// @dev Executes a call on address `target` with calldata `callData`
+    ///      and asserts that either nothing was returned or a single boolean
+    ///      was returned equal to `true`.
+    /// @param target The call target.
+    /// @param callData The abi-encoded call data.
+    function _callWithOptionalBooleanResult(
+        address target,
+        bytes memory callData
+    )
+        private
+    {
+        (bool didSucceed, bytes memory resultData) = target.call(callData);
+        if (didSucceed) {
+            if (resultData.length == 0) {
+                return;
+            }
+            if (resultData.length == 32) {
+                uint256 result = LibBytes.readUint256(resultData, 0);
+                if (result == 1) {
+                    return;
+                }
+            }
+        }
+        LibRichErrors.rrevert(resultData);
+    }
+}
--- a/contracts/tokens/contracts/tokens/ERC20Token/MintableERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/MintableERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,24 +16,25 @@

 */

-pragma solidity ^0.4.24;
+pragma solidity ^0.5.9;

-import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
+import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
 import "./UnlimitedAllowanceERC20Token.sol";


 contract MintableERC20Token is
-    SafeMath,
    UnlimitedAllowanceERC20Token
 {
+    using LibSafeMath for uint256;
+
    /// @dev Mints new tokens
    /// @param _to Address of the beneficiary that will own the minted token
    /// @param _value Amount of tokens to mint
    function _mint(address _to, uint256 _value)
        internal
    {
-        balances[_to] = safeAdd(_value, balances[_to]);
-        _totalSupply = safeAdd(_totalSupply, _value);
+        balances[_to] = _value.safeAdd(balances[_to]);
+        _totalSupply = _totalSupply.safeAdd(_value);

        emit Transfer(
            address(0),
@@ -48,8 +49,8 @@ contract MintableERC20Token is
    function _burn(address _owner, uint256 _value)
        internal
    {
-        balances[_owner] = safeSub(balances[_owner], _value);
-        _totalSupply = safeSub(_totalSupply, _value);
+        balances[_owner] = balances[_owner].safeSub(_value);
+        _totalSupply = _totalSupply.safeSub(_value);

        emit Transfer(
            _owner,
--- a/contracts/tokens/contracts/tokens/ERC20Token/UnlimitedAllowanceERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/UnlimitedAllowanceERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,9 +16,9 @@

 */

-pragma solidity ^0.4.24;
+pragma solidity ^0.5.9;

-import "../ERC20Token/ERC20Token.sol";
+import "./ERC20Token.sol";


 contract UnlimitedAllowanceERC20Token is
--- a/contracts/tokens/contracts/tokens/EtherToken/WETH9.sol
+++ b/contracts/tokens/contracts/tokens/EtherToken/WETH9.sol
@@ -14,7 +14,7 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.

 // solhint-disable
-pragma solidity ^0.4.18;
+pragma solidity ^0.5.9;


 contract WETH9 {
@@ -30,27 +30,27 @@ contract WETH9 {
    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

-    function() public payable {
+    function() external payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
-        Deposit(msg.sender, msg.value);
+        emit Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
-        Withdrawal(msg.sender, wad);
+        emit Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
-        return this.balance;
+        return address(this).balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
-        Approval(msg.sender, guy, wad);
+        emit Approval(msg.sender, guy, wad);
        return true;
    }

@@ -72,7 +72,7 @@ contract WETH9 {
        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

-        Transfer(src, dst, wad);
+        emit Transfer(src, dst, wad);

        return true;
    }
--- a/contracts/erc20/contracts/src/ZRXToken.sol
+++ b/contracts/erc20/contracts/src/ZRXToken.sol
@@ -0,0 +1,150 @@
+/*
+
+  Copyright 2019 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity 0.4.11;
+
+
+contract Token {
+
+    /// @return total amount of tokens
+    function totalSupply() constant returns (uint supply) {}
+
+    /// @param _owner The address from which the balance will be retrieved
+    /// @return The balance
+    function balanceOf(address _owner) constant returns (uint balance) {}
+
+    /// @notice send `_value` token to `_to` from `msg.sender`
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return Whether the transfer was successful or not
+    function transfer(address _to, uint _value) returns (bool success) {}
+
+    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
+    /// @param _from The address of the sender
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    /// @return Whether the transfer was successful or not
+    function transferFrom(address _from, address _to, uint _value) returns (bool success) {}
+
+    /// @notice `msg.sender` approves `_addr` to spend `_value` tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @param _value The amount of wei to be approved for transfer
+    /// @return Whether the approval was successful or not
+    function approve(address _spender, uint _value) returns (bool success) {}
+
+    /// @param _owner The address of the account owning tokens
+    /// @param _spender The address of the account able to transfer the tokens
+    /// @return Amount of remaining tokens allowed to spent
+    function allowance(address _owner, address _spender) constant returns (uint remaining) {}
+
+    event Transfer(address indexed _from, address indexed _to, uint _value);
+    event Approval(address indexed _owner, address indexed _spender, uint _value);
+}
+
+
+contract ERC20Token is Token {
+
+    function transfer(address _to, uint _value) returns (bool) {
+        //Default assumes totalSupply can't be over max (2^256 - 1).
+        if (balances[msg.sender] >= _value && balances[_to] + _value >= balances[_to]) {
+            balances[msg.sender] -= _value;
+            balances[_to] += _value;
+            Transfer(msg.sender, _to, _value);
+            return true;
+        } else { return false; }
+    }
+
+    function transferFrom(address _from, address _to, uint _value) returns (bool) {
+        if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && balances[_to] + _value >= balances[_to]) {
+            balances[_to] += _value;
+            balances[_from] -= _value;
+            allowed[_from][msg.sender] -= _value;
+            Transfer(_from, _to, _value);
+            return true;
+        } else { return false; }
+    }
+
+    function balanceOf(address _owner) constant returns (uint) {
+        return balances[_owner];
+    }
+
+    function approve(address _spender, uint _value) returns (bool) {
+        allowed[msg.sender][_spender] = _value;
+        Approval(msg.sender, _spender, _value);
+        return true;
+    }
+
+    function allowance(address _owner, address _spender) constant returns (uint) {
+        return allowed[_owner][_spender];
+    }
+
+    mapping (address => uint) balances;
+    mapping (address => mapping (address => uint)) allowed;
+    uint public totalSupply;
+}
+
+
+contract UnlimitedAllowanceToken is ERC20Token {
+
+    uint constant MAX_UINT = 2**256 - 1;
+
+    /// @dev ERC20 transferFrom, modified such that an allowance of MAX_UINT represents an unlimited allowance.
+    /// @param _from Address to transfer from.
+    /// @param _to Address to transfer to.
+    /// @param _value Amount to transfer.
+    /// @return Success of transfer.
+    function transferFrom(address _from, address _to, uint _value)
+        public
+        returns (bool)
+    {
+        uint allowance = allowed[_from][msg.sender];
+        if (balances[_from] >= _value
+            && allowance >= _value
+            && balances[_to] + _value >= balances[_to]
+        ) {
+            balances[_to] += _value;
+            balances[_from] -= _value;
+            if (allowance < MAX_UINT) {
+                allowed[_from][msg.sender] -= _value;
+            }
+            Transfer(_from, _to, _value);
+            return true;
+        } else {
+            return false;
+        }
+    }
+}
+
+
+contract ZRXToken is 
+    UnlimitedAllowanceToken
+{
+
+    // solhint-disable const-name-snakecase
+    uint8 constant public decimals = 18;
+    uint256 public totalSupply = 10**27; // 1 billion tokens, 18 decimal places
+    string constant public name = "0x Protocol Token";
+    string constant public symbol = "ZRX";
+    // solhint-enableconst-name-snakecase
+
+    function ZRXToken()
+        public
+    {
+        balances[msg.sender] = totalSupply;
+    }
+}
--- a/contracts/tokens/contracts/tokens/ERC20Token/IERC20Token.sol
+++ b/contracts/tokens/contracts/tokens/ERC20Token/IERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@

 */

-pragma solidity ^0.4.24;
+pragma solidity ^0.5.9;


 contract IERC20Token {
--- a/contracts/tokens/contracts/tokens/EtherToken/IEtherToken.sol
+++ b/contracts/tokens/contracts/tokens/EtherToken/IEtherToken.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,9 +16,9 @@

 */

-pragma solidity ^0.4.24;
+pragma solidity ^0.5.9;

-import "../ERC20Token/IERC20Token.sol";
+import "./IERC20Token.sol";


 contract IEtherToken is
--- a/contracts/erc20/contracts/src/v06/IERC20TokenV06.sol
+++ b/contracts/erc20/contracts/src/v06/IERC20TokenV06.sol
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2020 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+
+
+interface IERC20TokenV06 {
+
+    // solhint-disable no-simple-event-func-name
+    event Transfer(
+        address indexed from,
+        address indexed to,
+        uint256 value
+    );
+
+    event Approval(
+        address indexed owner,
+        address indexed spender,
+        uint256 value
+    );
+
+    /// @dev send `value` token to `to` from `msg.sender`
+    /// @param to The address of the recipient
+    /// @param value The amount of token to be transferred
+    /// @return True if transfer was successful
+    function transfer(address to, uint256 value)
+        external
+        returns (bool);
+
+    /// @dev send `value` token to `to` from `from` on the condition it is approved by `from`
+    /// @param from The address of the sender
+    /// @param to The address of the recipient
+    /// @param value The amount of token to be transferred
+    /// @return True if transfer was successful
+    function transferFrom(
+        address from,
+        address to,
+        uint256 value
+    )
+        external
+        returns (bool);
+
+    /// @dev `msg.sender` approves `spender` to spend `value` tokens
+    /// @param spender The address of the account able to transfer the tokens
+    /// @param value The amount of wei to be approved for transfer
+    /// @return Always true if the call has enough gas to complete execution
+    function approve(address spender, uint256 value)
+        external
+        returns (bool);
+
+    /// @dev Query total supply of token
+    /// @return Total supply of token
+    function totalSupply()
+        external
+        view
+        returns (uint256);
+
+    /// @dev Get the balance of `owner`.
+    /// @param owner The address from which the balance will be retrieved
+    /// @return Balance of owner
+    function balanceOf(address owner)
+        external
+        view
+        returns (uint256);
+
+    /// @dev Get the allowance for `spender` to spend from `owner`.
+    /// @param owner The address of the account owning tokens
+    /// @param spender The address of the account able to transfer the tokens
+    /// @return Amount of remaining tokens allowed to spent
+    function allowance(address owner, address spender)
+        external
+        view
+        returns (uint256);
+
+    /// @dev Get the number of decimals this token has.
+    function decimals()
+        external
+        view
+        returns (uint8);
+}
--- a/contracts/erc20/contracts/src/v06/IEtherTokenV06.sol
+++ b/contracts/erc20/contracts/src/v06/IEtherTokenV06.sol
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2020 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+
+import "./IERC20TokenV06.sol";
+
+
+interface IEtherTokenV06 is
+    IERC20TokenV06
+{
+    /// @dev Wrap ether.
+    function deposit() external payable;
+
+    /// @dev Unwrap ether.
+    function withdraw(uint256 amount) external;
+}
--- a/contracts/erc20/contracts/src/v06/LibERC20TokenV06.sol
+++ b/contracts/erc20/contracts/src/v06/LibERC20TokenV06.sol
@@ -0,0 +1,210 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2020 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+
+import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
+import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
+import "./IERC20TokenV06.sol";
+
+
+library LibERC20TokenV06 {
+    bytes constant private DECIMALS_CALL_DATA = hex"313ce567";
+
+    /// @dev Calls `IERC20TokenV06(token).approve()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param allowance The allowance to set.
+    function compatApprove(
+        IERC20TokenV06 token,
+        address spender,
+        uint256 allowance
+    )
+        internal
+    {
+        bytes memory callData = abi.encodeWithSelector(
+            token.approve.selector,
+            spender,
+            allowance
+        );
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Calls `IERC20TokenV06(token).approve()` and sets the allowance to the
+    ///      maximum if the current approval is not already >= an amount.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param spender The address that receives an allowance.
+    /// @param amount The minimum allowance needed.
+    function approveIfBelow(
+        IERC20TokenV06 token,
+        address spender,
+        uint256 amount
+    )
+        internal
+    {
+        if (token.allowance(address(this), spender) < amount) {
+            compatApprove(token, spender, uint256(-1));
+        }
+    }
+
+    /// @dev Calls `IERC20TokenV06(token).transfer()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function compatTransfer(
+        IERC20TokenV06 token,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        bytes memory callData = abi.encodeWithSelector(
+            token.transfer.selector,
+            to,
+            amount
+        );
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Calls `IERC20TokenV06(token).transferFrom()`.
+    ///      Reverts if the return data is invalid or the call reverts.
+    /// @param token The address of the token contract.
+    /// @param from The owner of the tokens.
+    /// @param to The address that receives the tokens
+    /// @param amount Number of tokens to transfer.
+    function compatTransferFrom(
+        IERC20TokenV06 token,
+        address from,
+        address to,
+        uint256 amount
+    )
+        internal
+    {
+        bytes memory callData = abi.encodeWithSelector(
+            token.transferFrom.selector,
+            from,
+            to,
+            amount
+        );
+        _callWithOptionalBooleanResult(address(token), callData);
+    }
+
+    /// @dev Retrieves the number of decimals for a token.
+    ///      Returns `18` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @return tokenDecimals The number of decimals places for the token.
+    function compatDecimals(IERC20TokenV06 token)
+        internal
+        view
+        returns (uint8 tokenDecimals)
+    {
+        tokenDecimals = 18;
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(DECIMALS_CALL_DATA);
+        if (didSucceed && resultData.length >= 32) {
+            tokenDecimals = uint8(LibBytesV06.readUint256(resultData, 0));
+        }
+    }
+
+    /// @dev Retrieves the allowance for a token, owner, and spender.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @param spender The address the spender.
+    /// @return allowance_ The allowance for a token, owner, and spender.
+    function compatAllowance(IERC20TokenV06 token, address owner, address spender)
+        internal
+        view
+        returns (uint256 allowance_)
+    {
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(
+            abi.encodeWithSelector(
+                token.allowance.selector,
+                owner,
+                spender
+            )
+        );
+        if (didSucceed && resultData.length >= 32) {
+            allowance_ = LibBytesV06.readUint256(resultData, 0);
+        }
+    }
+
+    /// @dev Retrieves the balance for a token owner.
+    ///      Returns `0` if the call reverts.
+    /// @param token The address of the token contract.
+    /// @param owner The owner of the tokens.
+    /// @return balance The token balance of an owner.
+    function compatBalanceOf(IERC20TokenV06 token, address owner)
+        internal
+        view
+        returns (uint256 balance)
+    {
+        (bool didSucceed, bytes memory resultData) = address(token).staticcall(
+            abi.encodeWithSelector(
+                token.balanceOf.selector,
+                owner
+            )
+        );
+        if (didSucceed && resultData.length >= 32) {
+            balance = LibBytesV06.readUint256(resultData, 0);
+        }
+    }
+
+    /// @dev Executes a call on address `target` with calldata `callData`
+    ///      and asserts that either nothing was returned or a single boolean
+    ///      was returned equal to `true`.
+    /// @param target The call target.
+    /// @param callData The abi-encoded call data.
+    function _callWithOptionalBooleanResult(
+        address target,
+        bytes memory callData
+    )
+        private
+    {
+        (bool didSucceed, bytes memory resultData) = target.call(callData);
+        // Revert if the call reverted.
+        if (!didSucceed) {
+            LibRichErrorsV06.rrevert(resultData);
+        }
+        // If we get back 0 returndata, this may be a non-standard ERC-20 that
+        // does not return a boolean. Check that it at least contains code.
+        if (resultData.length == 0) {
+            uint256 size;
+            assembly { size := extcodesize(target) }
+            require(size > 0, "invalid token address, contains no code");
+            return;
+        }
+        // If we get back at least 32 bytes, we know the target address
+        // contains code, and we assume it is a token that returned a boolean
+        // success value, which must be true.
+        if (resultData.length >= 32) {
+            uint256 result = LibBytesV06.readUint256(resultData, 0);
+            if (result == 1) {
+                return;
+            } else {
+                LibRichErrorsV06.rrevert(resultData);
+            }
+        }
+        // If 0 < returndatasize < 32, the target is a contract, but not a
+        // valid token.
+        LibRichErrorsV06.rrevert(resultData);
+    }
+}
--- a/contracts/tokens/contracts/test/DummyERC20Token/DummyERC20Token.sol
+++ b/contracts/tokens/contracts/test/DummyERC20Token/DummyERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,24 +16,27 @@

 */

-pragma solidity 0.4.24;
+pragma solidity ^0.5.5;

-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "../../tokens/ERC20Token/MintableERC20Token.sol";
+import "@0x/contracts-utils/contracts/src/LibSafeMath.sol";
+import "@0x/contracts-utils/contracts/src/Ownable.sol";
+import "../src/MintableERC20Token.sol";


 contract DummyERC20Token is
    Ownable,
    MintableERC20Token
 {
+    using LibSafeMath for uint256;
+
    string public name;
    string public symbol;
    uint256 public decimals;
    uint256 public constant MAX_MINT_AMOUNT = 10000000000000000000000;

    constructor (
-        string _name,
-        string _symbol,
+        string memory _name,
+        string memory _symbol,
        uint256 _decimals,
        uint256 _totalSupply
    )
@@ -55,9 +58,9 @@ contract DummyERC20Token is
    {
        uint256 currBalance = balances[_target];
        if (_value < currBalance) {
-            _totalSupply = safeSub(_totalSupply, safeSub(currBalance, _value));
+            _totalSupply = _totalSupply.safeSub(currBalance.safeSub(_value));
        } else {
-            _totalSupply = safeAdd(_totalSupply, safeSub(_value, currBalance));
+            _totalSupply = _totalSupply.safeAdd(_value.safeSub(currBalance));
        }
        balances[_target] = _value;
    }
--- a/contracts/tokens/contracts/test/DummyERC20Token/DummyMultipleReturnERC20Token.sol
+++ b/contracts/tokens/contracts/test/DummyERC20Token/DummyMultipleReturnERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@

 */

-pragma solidity 0.4.24;
+pragma solidity ^0.5.5;

 import "./DummyERC20Token.sol";

@@ -26,8 +26,8 @@ contract DummyMultipleReturnERC20Token is
    DummyERC20Token
 {
    constructor (
-        string _name,
-        string _symbol,
+        string memory _name,
+        string memory _symbol,
        uint256 _decimals,
        uint256 _totalSupply
    )
--- a/contracts/tokens/contracts/test/DummyERC20Token/DummyNoReturnERC20Token.sol
+++ b/contracts/tokens/contracts/test/DummyERC20Token/DummyNoReturnERC20Token.sol
@@ -1,6 +1,6 @@
 /*

-  Copyright 2018 ZeroEx Intl.
+  Copyright 2019 ZeroEx Intl.

  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
@@ -16,7 +16,7 @@

 */

-pragma solidity 0.4.24;
+pragma solidity ^0.5.5;

 import "./DummyERC20Token.sol";

@@ -26,8 +26,8 @@ contract DummyNoReturnERC20Token is
    DummyERC20Token
 {
    constructor (
-        string _name,
-        string _symbol,
+        string memory _name,
+        string memory _symbol,
        uint256 _decimals,
        uint256 _totalSupply
    )
--- a/contracts/erc20/contracts/test/TestLibERC20Token.sol
+++ b/contracts/erc20/contracts/test/TestLibERC20Token.sol
@@ -0,0 +1,84 @@
+/*
+
+  Copyright 2019 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.5.9;
+
+import "../src/LibERC20Token.sol";
+import "./TestLibERC20TokenTarget.sol";
+
+
+contract TestLibERC20Token {
+
+    TestLibERC20TokenTarget public target;
+
+    constructor() public {
+        target = new TestLibERC20TokenTarget();
+    }
+
+    function testApprove(
+        bool shouldRevert,
+        bytes calldata revertData,
+        bytes calldata returnData,
+        address spender,
+        uint256 allowance
+    )
+        external
+    {
+        target.setBehavior(shouldRevert, revertData, returnData);
+        LibERC20Token.approve(address(target), spender, allowance);
+    }
+
+    function testTransfer(
+        bool shouldRevert,
+        bytes calldata revertData,
+        bytes calldata returnData,
+        address to,
+        uint256 amount
+    )
+        external
+    {
+        target.setBehavior(shouldRevert, revertData, returnData);
+        LibERC20Token.transfer(address(target), to, amount);
+    }
+
+    function testTransferFrom(
+        bool shouldRevert,
+        bytes calldata revertData,
+        bytes calldata returnData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        external
+    {
+        target.setBehavior(shouldRevert, revertData, returnData);
+        LibERC20Token.transferFrom(address(target), from, to, amount);
+    }
+
+    function testDecimals(
+        bool shouldRevert,
+        bytes calldata revertData,
+        bytes calldata returnData
+    )
+        external
+        returns (uint8)
+    {
+        target.setBehavior(shouldRevert, revertData, returnData);
+        return LibERC20Token.decimals(address(target));
+    }
+}
--- a/contracts/erc20/contracts/test/TestLibERC20TokenTarget.sol
+++ b/contracts/erc20/contracts/test/TestLibERC20TokenTarget.sol
@@ -0,0 +1,106 @@
+/*
+
+  Copyright 2019 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.5.9;
+
+
+contract TestLibERC20TokenTarget {
+
+    event ApproveCalled(
+        address spender,
+        uint256 allowance
+    );
+
+    event TransferCalled(
+        address to,
+        uint256 amount
+    );
+
+    event TransferFromCalled(
+        address from,
+        address to,
+        uint256 amount
+    );
+
+    bool private _shouldRevert;
+    bytes private _revertData;
+    bytes private _returnData;
+
+    function setBehavior(
+        bool shouldRevert,
+        bytes calldata revertData,
+        bytes calldata returnData
+    )
+        external
+    {
+        _shouldRevert = shouldRevert;
+        _revertData = revertData;
+        _returnData = returnData;
+    }
+
+    function approve(
+        address spender,
+        uint256 allowance
+    )
+        external
+        returns (bool)
+    {
+        emit ApproveCalled(spender, allowance);
+        _execute();
+    }
+
+    function transfer(
+        address to,
+        uint256 amount
+    )
+        external
+        returns (bool)
+    {
+        emit TransferCalled(to, amount);
+        _execute();
+    }
+
+    function transferFrom(
+        address from,
+        address to,
+        uint256 amount
+    )
+        external
+        returns (bool)
+    {
+        emit TransferFromCalled(from, to, amount);
+        _execute();
+    }
+
+    function decimals()
+        external
+        view
+        returns (uint8)
+    {
+        _execute();
+    }
+
+    function _execute() private view {
+        if (_shouldRevert) {
+            bytes memory revertData = _revertData;
+            assembly { revert(add(revertData, 0x20), mload(revertData)) }
+        }
+        bytes memory returnData = _returnData;
+        assembly { return(add(returnData, 0x20), mload(returnData)) }
+    }
+}
--- a/contracts/erc20/contracts/test/UntransferrableDummyERC20Token.sol
+++ b/contracts/erc20/contracts/test/UntransferrableDummyERC20Token.sol
@@ -0,0 +1,62 @@
+/*
+
+  Copyright 2019 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.5.5;
+
+import "./DummyERC20Token.sol";
+
+
+// solhint-disable no-empty-blocks
+// solhint-disable no-unused-vars
+contract UntransferrableDummyERC20Token is
+    DummyERC20Token
+{
+    constructor (
+        string memory _name,
+        string memory _symbol,
+        uint256 _decimals,
+        uint256 _totalSupply
+    )
+        public
+        DummyERC20Token(
+            _name,
+            _symbol,
+            _decimals,
+            _totalSupply
+        )
+    {}
+
+    /// @dev send `value` token to `to` from `from` on the condition it is approved by `from`
+    /// @param _from The address of the sender
+    /// @param _to The address of the recipient
+    /// @param _value The amount of token to be transferred
+    function transferFrom(
+        address _from,
+        address _to,
+        uint256 _value
+    )
+        external
+        returns (bool)
+    {
+        require(
+            false,
+            "TRANSFER_DISABLED"
+        );
+    }
+}
+
--- a/contracts/erc20/package.json
+++ b/contracts/erc20/package.json
@@ -0,0 +1,92 @@
+{
+    "name": "@0x/contracts-erc20",
+    "version": "3.3.31",
+    "engines": {
+        "node": ">=6.12"
+    },
+    "description": "Token contracts used by 0x protocol",
+    "main": "lib/src/index.js",
+    "directories": {
+        "test": "test"
+    },
+    "scripts": {
+        "build": "yarn pre_build && tsc -b",
+        "build:ci": "yarn build",
+        "pre_build": "run-s compile contracts:gen generate_contract_wrappers contracts:copy",
+        "test": "yarn run_mocha",
+        "rebuild_and_test": "run-s build test",
+        "test:coverage": "SOLIDITY_COVERAGE=true run-s build run_mocha coverage:report:text coverage:report:lcov",
+        "test:profiler": "SOLIDITY_PROFILER=true run-s build run_mocha profiler:report:html",
+        "test:trace": "SOLIDITY_REVERT_TRACE=true run-s build run_mocha",
+        "run_mocha": "mocha --require source-map-support/register --require make-promises-safe 'lib/test/**/*.js' --timeout 100000 --bail --exit",
+        "compile": "sol-compiler",
+        "watch": "sol-compiler -w",
+        "clean": "shx rm -rf lib test/generated-artifacts test/generated-wrappers generated-artifacts generated-wrappers",
+        "generate_contract_wrappers": "abi-gen --debug --abis  ${npm_package_config_abis} --output test/generated-wrappers --backend ethers",
+        "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./test/generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude ./test/generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
+        "fix": "tslint --fix --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./test/generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude ./test/generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
+        "coverage:report:text": "istanbul report text",
+        "coverage:report:html": "istanbul report html && open coverage/index.html",
+        "profiler:report:html": "istanbul report html && open coverage/index.html",
+        "coverage:report:lcov": "istanbul report lcov",
+        "test:circleci": "yarn test",
+        "contracts:gen": "contracts-gen generate",
+        "contracts:copy": "contracts-gen copy",
+        "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol",
+        "docs:md": "ts-doc-gen --sourceDir='$PROJECT_FILES' --output=$MD_FILE_DIR --fileExtension=mdx --tsconfig=./typedoc-tsconfig.json",
+        "docs:json": "typedoc --excludePrivate --excludeExternals --excludeProtected --ignoreCompilerErrors --target ES5 --tsconfig typedoc-tsconfig.json --json $JSON_FILE_PATH $PROJECT_FILES"
+    },
+    "config": {
+        "publicInterfaceContracts": "DummyERC20Token,ERC20Token,WETH9,ZRXToken,DummyNoReturnERC20Token,DummyMultipleReturnERC20Token",
+        "abis": "./test/generated-artifacts/@(DummyERC20Token|DummyMultipleReturnERC20Token|DummyNoReturnERC20Token|ERC20Token|IERC20Token|IERC20TokenV06|IEtherToken|IEtherTokenV06|LibERC20Token|LibERC20TokenV06|MintableERC20Token|TestLibERC20Token|TestLibERC20TokenTarget|UnlimitedAllowanceERC20Token|UntransferrableDummyERC20Token|WETH9|ZRXToken).json",
+        "abis:comment": "This list is auto-generated by contracts-gen. Don't edit manually."
+    },
+    "repository": {
+        "type": "git",
+        "url": "https://github.com/0xProject/protocol.git"
+    },
+    "license": "Apache-2.0",
+    "bugs": {
+        "url": "https://github.com/0xProject/protocol/issues"
+    },
+    "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/tokens",
+    "devDependencies": {
+        "@0x/abi-gen": "^5.8.0",
+        "@0x/contracts-gen": "^2.0.46",
+        "@0x/contracts-test-utils": "^5.4.22",
+        "@0x/contracts-utils": "^4.8.12",
+        "@0x/dev-utils": "^4.2.14",
+        "@0x/sol-compiler": "^4.8.1",
+        "@0x/ts-doc-gen": "^0.0.28",
+        "@0x/tslint-config": "^4.1.4",
+        "@0x/types": "^3.3.6",
+        "@0x/typescript-typings": "^5.3.1",
+        "@0x/utils": "^6.5.3",
+        "@0x/web3-wrapper": "^7.6.5",
+        "@types/lodash": "4.14.104",
+        "@types/mocha": "^5.2.7",
+        "@types/node": "12.12.54",
+        "chai": "^4.0.1",
+        "chai-as-promised": "^7.1.0",
+        "chai-bignumber": "^3.0.0",
+        "dirty-chai": "^2.0.1",
+        "ethereum-types": "^3.7.0",
+        "lodash": "^4.17.11",
+        "make-promises-safe": "^1.1.0",
+        "mocha": "^6.2.0",
+        "npm-run-all": "^4.1.2",
+        "shx": "^0.2.2",
+        "solhint": "^1.4.1",
+        "tslint": "5.11.0",
+        "typedoc": "~0.16.11",
+        "typescript": "4.6.3"
+    },
+    "dependencies": {
+        "@0x/base-contract": "^6.5.0",
+        "ethers": "~4.0.4"
+    },
+    "publishConfig": {
+        "access": "public"
+    },
+    "gitHead": "4f91bfd907996b2f4dd383778b50c479c2602b56"
+}
--- a/contracts/erc20/src/artifacts.ts
+++ b/contracts/erc20/src/artifacts.ts
@@ -0,0 +1,21 @@
+/*
+ * -----------------------------------------------------------------------------
+ * Warning: This file is auto-generated by contracts-gen. Don't edit manually.
+ * -----------------------------------------------------------------------------
+ */
+import { ContractArtifact } from 'ethereum-types';
+
+import * as DummyERC20Token from '../generated-artifacts/DummyERC20Token.json';
+import * as DummyMultipleReturnERC20Token from '../generated-artifacts/DummyMultipleReturnERC20Token.json';
+import * as DummyNoReturnERC20Token from '../generated-artifacts/DummyNoReturnERC20Token.json';
+import * as ERC20Token from '../generated-artifacts/ERC20Token.json';
+import * as WETH9 from '../generated-artifacts/WETH9.json';
+import * as ZRXToken from '../generated-artifacts/ZRXToken.json';
+export const artifacts = {
+    DummyERC20Token: DummyERC20Token as ContractArtifact,
+    ERC20Token: ERC20Token as ContractArtifact,
+    WETH9: WETH9 as ContractArtifact,
+    ZRXToken: (ZRXToken as any) as ContractArtifact,
+    DummyNoReturnERC20Token: DummyNoReturnERC20Token as ContractArtifact,
+    DummyMultipleReturnERC20Token: DummyMultipleReturnERC20Token as ContractArtifact,
+};
--- a/contracts/erc20/src/index.ts
+++ b/contracts/erc20/src/index.ts
@@ -0,0 +1,47 @@
+export {
+    DummyERC20TokenContract,
+    DummyMultipleReturnERC20TokenContract,
+    DummyNoReturnERC20TokenContract,
+    WETH9Contract,
+    WETH9Events,
+    WETH9DepositEventArgs,
+    WETH9TransferEventArgs,
+    WETH9WithdrawalEventArgs,
+    ZRXTokenContract,
+    DummyERC20TokenTransferEventArgs,
+    ERC20TokenEventArgs,
+    ERC20TokenEvents,
+    ERC20TokenTransferEventArgs,
+    ERC20TokenApprovalEventArgs,
+    ERC20TokenContract,
+} from './wrappers';
+export { artifacts } from './artifacts';
+export {
+    ContractArtifact,
+    ContractChains,
+    CompilerOpts,
+    StandardContractOutput,
+    CompilerSettings,
+    ContractChainData,
+    ContractAbi,
+    DevdocOutput,
+    EvmOutput,
+    CompilerSettingsMetadata,
+    OptimizerSettings,
+    OutputField,
+    ParamDescription,
+    EvmBytecodeOutput,
+    EvmBytecodeOutputLinkReferences,
+    AbiDefinition,
+    FunctionAbi,
+    EventAbi,
+    RevertErrorAbi,
+    EventParameter,
+    DataItem,
+    MethodAbi,
+    ConstructorAbi,
+    FallbackAbi,
+    ConstructorStateMutability,
+    TupleDataItem,
+    StateMutability,
+} from 'ethereum-types';
--- a/contracts/erc20/src/wrappers.ts
+++ b/contracts/erc20/src/wrappers.ts
@@ -0,0 +1,11 @@
+/*
+ * -----------------------------------------------------------------------------
+ * Warning: This file is auto-generated by contracts-gen. Don't edit manually.
+ * -----------------------------------------------------------------------------
+ */
+export * from '../generated-wrappers/dummy_erc20_token';
+export * from '../generated-wrappers/dummy_multiple_return_erc20_token';
+export * from '../generated-wrappers/dummy_no_return_erc20_token';
+export * from '../generated-wrappers/erc20_token';
+export * from '../generated-wrappers/weth9';
+export * from '../generated-wrappers/zrx_token';
--- a/contracts/erc20/test/artifacts.ts
+++ b/contracts/erc20/test/artifacts.ts
@@ -0,0 +1,43 @@
+/*
+ * -----------------------------------------------------------------------------
+ * Warning: This file is auto-generated by contracts-gen. Don't edit manually.
+ * -----------------------------------------------------------------------------
+ */
+import { ContractArtifact } from 'ethereum-types';
+
+import * as DummyERC20Token from '../test/generated-artifacts/DummyERC20Token.json';
+import * as DummyMultipleReturnERC20Token from '../test/generated-artifacts/DummyMultipleReturnERC20Token.json';
+import * as DummyNoReturnERC20Token from '../test/generated-artifacts/DummyNoReturnERC20Token.json';
+import * as ERC20Token from '../test/generated-artifacts/ERC20Token.json';
+import * as IERC20Token from '../test/generated-artifacts/IERC20Token.json';
+import * as IERC20TokenV06 from '../test/generated-artifacts/IERC20TokenV06.json';
+import * as IEtherToken from '../test/generated-artifacts/IEtherToken.json';
+import * as IEtherTokenV06 from '../test/generated-artifacts/IEtherTokenV06.json';
+import * as LibERC20Token from '../test/generated-artifacts/LibERC20Token.json';
+import * as LibERC20TokenV06 from '../test/generated-artifacts/LibERC20TokenV06.json';
+import * as MintableERC20Token from '../test/generated-artifacts/MintableERC20Token.json';
+import * as TestLibERC20Token from '../test/generated-artifacts/TestLibERC20Token.json';
+import * as TestLibERC20TokenTarget from '../test/generated-artifacts/TestLibERC20TokenTarget.json';
+import * as UnlimitedAllowanceERC20Token from '../test/generated-artifacts/UnlimitedAllowanceERC20Token.json';
+import * as UntransferrableDummyERC20Token from '../test/generated-artifacts/UntransferrableDummyERC20Token.json';
+import * as WETH9 from '../test/generated-artifacts/WETH9.json';
+import * as ZRXToken from '../test/generated-artifacts/ZRXToken.json';
+export const artifacts = {
+    ERC20Token: ERC20Token as ContractArtifact,
+    LibERC20Token: LibERC20Token as ContractArtifact,
+    MintableERC20Token: MintableERC20Token as ContractArtifact,
+    UnlimitedAllowanceERC20Token: UnlimitedAllowanceERC20Token as ContractArtifact,
+    WETH9: WETH9 as ContractArtifact,
+    ZRXToken: (ZRXToken as any) as ContractArtifact,
+    IERC20Token: IERC20Token as ContractArtifact,
+    IEtherToken: IEtherToken as ContractArtifact,
+    IERC20TokenV06: IERC20TokenV06 as ContractArtifact,
+    IEtherTokenV06: IEtherTokenV06 as ContractArtifact,
+    LibERC20TokenV06: LibERC20TokenV06 as ContractArtifact,
+    DummyERC20Token: DummyERC20Token as ContractArtifact,
+    DummyMultipleReturnERC20Token: DummyMultipleReturnERC20Token as ContractArtifact,
+    DummyNoReturnERC20Token: DummyNoReturnERC20Token as ContractArtifact,
+    TestLibERC20Token: TestLibERC20Token as ContractArtifact,
+    TestLibERC20TokenTarget: TestLibERC20TokenTarget as ContractArtifact,
+    UntransferrableDummyERC20Token: UntransferrableDummyERC20Token as ContractArtifact,
+};
--- a/contracts/erc20/test/global_hooks.ts
+++ b/contracts/erc20/test/global_hooks.ts
@@ -0,0 +1,19 @@
+import { env, EnvVars } from '@0x/dev-utils';
+
+import { coverage, profiler, provider } from '@0x/contracts-test-utils';
+import { providerUtils } from '@0x/utils';
+
+before('start web3 provider', () => {
+    providerUtils.startProviderEngine(provider);
+});
+after('generate coverage report', async () => {
+    if (env.parseBoolean(EnvVars.SolidityCoverage)) {
+        const coverageSubprovider = coverage.getCoverageSubproviderSingleton();
+        await coverageSubprovider.writeCoverageAsync();
+    }
+    if (env.parseBoolean(EnvVars.SolidityProfiler)) {
+        const profilerSubprovider = profiler.getProfilerSubproviderSingleton();
+        await profilerSubprovider.writeProfilerOutputAsync();
+    }
+    provider.stop();
+});
--- a/contracts/erc20/test/lib_erc20_token.ts
+++ b/contracts/erc20/test/lib_erc20_token.ts
@@ -0,0 +1,335 @@
+import {
+    blockchainTests,
+    constants,
+    expect,
+    getRandomInteger,
+    randomAddress,
+    verifyEventsFromLogs,
+} from '@0x/contracts-test-utils';
+import { hexUtils, RawRevertError, StringRevertError } from '@0x/utils';
+
+import { TestLibERC20TokenContract, TestLibERC20TokenTargetEvents } from './wrappers';
+
+import { artifacts } from './artifacts';
+
+blockchainTests('LibERC20Token', env => {
+    let testContract: TestLibERC20TokenContract;
+    const REVERT_STRING = 'WHOOPSIE';
+    const ENCODED_REVERT = new StringRevertError(REVERT_STRING).encode();
+    const ENCODED_TRUE = hexUtils.leftPad(1);
+    const ENCODED_FALSE = hexUtils.leftPad(0);
+    const ENCODED_TWO = hexUtils.leftPad(2);
+    const ENCODED_SHORT_TRUE = hexUtils.leftPad(2, 31);
+    const ENCODED_LONG_TRUE = hexUtils.leftPad(2, 33);
+
+    before(async () => {
+        testContract = await TestLibERC20TokenContract.deployFrom0xArtifactAsync(
+            artifacts.TestLibERC20Token,
+            env.provider,
+            env.txDefaults,
+            artifacts,
+        );
+    });
+
+    describe('approve()', () => {
+        it('calls the target with the correct arguments', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const { logs } = await testContract
+                .testApprove(false, ENCODED_REVERT, ENCODED_TRUE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            expect(logs).to.be.length(1);
+            verifyEventsFromLogs(logs, [{ spender, allowance }], TestLibERC20TokenTargetEvents.ApproveCalled);
+        });
+
+        it('succeeds if the target returns true', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            await testContract
+                .testApprove(false, ENCODED_REVERT, ENCODED_TRUE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+        });
+
+        it('succeeds if the target returns nothing', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            await testContract
+                .testApprove(false, ENCODED_REVERT, constants.NULL_BYTES, spender, allowance)
+                .awaitTransactionSuccessAsync();
+        });
+
+        it('fails if the target returns false', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testApprove(false, ENCODED_REVERT, ENCODED_FALSE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_FALSE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns nonzero and not true', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testApprove(false, ENCODED_REVERT, ENCODED_TWO, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_TWO);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns less than 32 bytes', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testApprove(false, ENCODED_REVERT, ENCODED_SHORT_TRUE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_SHORT_TRUE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns greater than 32 bytes', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testApprove(false, ENCODED_REVERT, ENCODED_LONG_TRUE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_LONG_TRUE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target reverts', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testApprove(true, ENCODED_REVERT, ENCODED_TRUE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            return expect(tx).to.revertWith(REVERT_STRING);
+        });
+
+        it('fails if the target reverts with no data', async () => {
+            const spender = randomAddress();
+            const allowance = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testApprove(true, constants.NULL_BYTES, ENCODED_TRUE, spender, allowance)
+                .awaitTransactionSuccessAsync();
+            return expect(tx).to.be.rejectedWith('revert');
+        });
+    });
+
+    describe('transfer()', () => {
+        it('calls the target with the correct arguments', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const { logs } = await testContract
+                .testTransfer(false, ENCODED_REVERT, ENCODED_TRUE, to, amount)
+                .awaitTransactionSuccessAsync();
+            expect(logs).to.be.length(1);
+            verifyEventsFromLogs(logs, [{ to, amount }], TestLibERC20TokenTargetEvents.TransferCalled);
+        });
+
+        it('succeeds if the target returns true', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            await testContract
+                .testTransfer(false, ENCODED_REVERT, ENCODED_TRUE, to, amount)
+                .awaitTransactionSuccessAsync();
+        });
+
+        it('succeeds if the target returns nothing', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            await testContract
+                .testTransfer(false, ENCODED_REVERT, constants.NULL_BYTES, to, amount)
+                .awaitTransactionSuccessAsync();
+        });
+
+        it('fails if the target returns false', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransfer(false, ENCODED_REVERT, ENCODED_FALSE, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_FALSE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns nonzero and not true', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransfer(false, ENCODED_REVERT, ENCODED_TWO, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_TWO);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns less than 32 bytes', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransfer(false, ENCODED_REVERT, ENCODED_SHORT_TRUE, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_SHORT_TRUE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns greater than 32 bytes', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransfer(false, ENCODED_REVERT, ENCODED_LONG_TRUE, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_LONG_TRUE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target reverts', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransfer(true, ENCODED_REVERT, ENCODED_TRUE, to, amount)
+                .awaitTransactionSuccessAsync();
+            return expect(tx).to.revertWith(REVERT_STRING);
+        });
+
+        it('fails if the target reverts with no data', async () => {
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransfer(true, constants.NULL_BYTES, ENCODED_TRUE, to, amount)
+                .awaitTransactionSuccessAsync();
+            return expect(tx).to.be.rejectedWith('revert');
+        });
+    });
+
+    describe('transferFrom()', () => {
+        it('calls the target with the correct arguments', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const { logs } = await testContract
+                .testTransferFrom(false, ENCODED_REVERT, ENCODED_TRUE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            expect(logs).to.be.length(1);
+            verifyEventsFromLogs(logs, [{ from: owner, to, amount }], TestLibERC20TokenTargetEvents.TransferFromCalled);
+        });
+
+        it('succeeds if the target returns true', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            await testContract
+                .testTransferFrom(false, ENCODED_REVERT, ENCODED_TRUE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+        });
+
+        it('succeeds if the target returns nothing', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            await testContract
+                .testTransferFrom(false, ENCODED_REVERT, constants.NULL_BYTES, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+        });
+
+        it('fails if the target returns false', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransferFrom(false, ENCODED_REVERT, ENCODED_FALSE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_FALSE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns nonzero and not true', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransferFrom(false, ENCODED_REVERT, ENCODED_TWO, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_TWO);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns less than 32 bytes', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransferFrom(false, ENCODED_REVERT, ENCODED_SHORT_TRUE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_SHORT_TRUE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target returns greater than 32 bytes', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransferFrom(false, ENCODED_REVERT, ENCODED_LONG_TRUE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            const expectedError = new RawRevertError(ENCODED_LONG_TRUE);
+            return expect(tx).to.revertWith(expectedError);
+        });
+
+        it('fails if the target reverts', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransferFrom(true, ENCODED_REVERT, ENCODED_TRUE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            return expect(tx).to.revertWith(REVERT_STRING);
+        });
+
+        it('fails if the target reverts with no data', async () => {
+            const owner = randomAddress();
+            const to = randomAddress();
+            const amount = getRandomInteger(0, 100e18);
+            const tx = testContract
+                .testTransferFrom(true, constants.NULL_BYTES, ENCODED_TRUE, owner, to, amount)
+                .awaitTransactionSuccessAsync();
+            return expect(tx).to.be.rejectedWith('revert');
+        });
+    });
+
+    describe('decimals()', () => {
+        const DEFAULT_DECIMALS = 18;
+        const ENCODED_ZERO = hexUtils.leftPad(0);
+        const ENCODED_SHORT_ZERO = hexUtils.leftPad(0, 31);
+        const ENCODED_LONG_ZERO = hexUtils.leftPad(0, 33);
+        const randomDecimals = () => Math.floor(Math.random() * 256) + 1;
+
+        it('returns the number of decimals defined by the token', async () => {
+            const decimals = randomDecimals();
+            const encodedDecimals = hexUtils.leftPad(decimals);
+            const result = await testContract.testDecimals(false, ENCODED_REVERT, encodedDecimals).callAsync();
+            return expect(result).to.bignumber.eq(decimals);
+        });
+
+        it('returns 0 if the token returns 0', async () => {
+            const result = await testContract.testDecimals(false, ENCODED_REVERT, ENCODED_ZERO).callAsync();
+            return expect(result).to.bignumber.eq(0);
+        });
+
+        it('returns 18 if the token returns less than 32 bytes', async () => {
+            const result = await testContract.testDecimals(false, ENCODED_REVERT, ENCODED_SHORT_ZERO).callAsync();
+            return expect(result).to.bignumber.eq(DEFAULT_DECIMALS);
+        });
+
+        it('returns 18 if the token returns greater than 32 bytes', async () => {
+            const result = await testContract.testDecimals(false, ENCODED_REVERT, ENCODED_LONG_ZERO).callAsync();
+            return expect(result).to.bignumber.eq(DEFAULT_DECIMALS);
+        });
+
+        it('returns 18 if the token reverts', async () => {
+            const result = await testContract.testDecimals(true, ENCODED_REVERT, ENCODED_ZERO).callAsync();
+            return expect(result).to.bignumber.eq(DEFAULT_DECIMALS);
+        });
+    });
+});
--- a/contracts/erc20/test/unlimited_allowance_token.ts
+++ b/contracts/erc20/test/unlimited_allowance_token.ts
@@ -0,0 +1,187 @@
+import { chaiSetup, constants, provider, txDefaults, web3Wrapper } from '@0x/contracts-test-utils';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { RevertReason } from '@0x/types';
+import { BigNumber } from '@0x/utils';
+import * as chai from 'chai';
+
+import { DummyERC20TokenContract } from './wrappers';
+
+import { artifacts } from './artifacts';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('UnlimitedAllowanceToken', () => {
+    let owner: string;
+    let spender: string;
+    const MAX_MINT_VALUE = new BigNumber(10000000000000000000000);
+    let token: DummyERC20TokenContract;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        owner = accounts[0];
+        spender = accounts[1];
+        token = await DummyERC20TokenContract.deployFrom0xArtifactAsync(
+            artifacts.DummyERC20Token,
+            provider,
+            txDefaults,
+            artifacts,
+            constants.DUMMY_TOKEN_NAME,
+            constants.DUMMY_TOKEN_SYMBOL,
+            constants.DUMMY_TOKEN_DECIMALS,
+            constants.DUMMY_TOKEN_TOTAL_SUPPLY,
+        );
+        await web3Wrapper.awaitTransactionSuccessAsync(
+            await token.mint(MAX_MINT_VALUE).sendTransactionAsync({ from: owner }),
+            constants.AWAIT_TRANSACTION_MINED_MS,
+        );
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('transfer', () => {
+        it('should revert if owner has insufficient balance', async () => {
+            const ownerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = ownerBalance.plus(1);
+            return expect(token.transfer(spender, amountToTransfer).callAsync({ from: owner })).to.revertWith(
+                RevertReason.Erc20InsufficientBalance,
+            );
+        });
+
+        it('should transfer balance from sender to receiver', async () => {
+            const receiver = spender;
+            const initOwnerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = new BigNumber(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.transfer(receiver, amountToTransfer).sendTransactionAsync({ from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const finalOwnerBalance = await token.balanceOf(owner).callAsync();
+            const finalReceiverBalance = await token.balanceOf(receiver).callAsync();
+
+            const expectedFinalOwnerBalance = initOwnerBalance.minus(amountToTransfer);
+            const expectedFinalReceiverBalance = amountToTransfer;
+            expect(finalOwnerBalance).to.be.bignumber.equal(expectedFinalOwnerBalance);
+            expect(finalReceiverBalance).to.be.bignumber.equal(expectedFinalReceiverBalance);
+        });
+
+        it('should return true on a 0 value transfer', async () => {
+            const didReturnTrue = await token.transfer(spender, new BigNumber(0)).callAsync({
+                from: owner,
+            });
+            expect(didReturnTrue).to.be.true();
+        });
+    });
+
+    describe('transferFrom', () => {
+        it('should revert if owner has insufficient balance', async () => {
+            const ownerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = ownerBalance.plus(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.approve(spender, amountToTransfer).sendTransactionAsync({ from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            return expect(
+                token.transferFrom(owner, spender, amountToTransfer).callAsync({
+                    from: spender,
+                }),
+            ).to.revertWith(RevertReason.Erc20InsufficientBalance);
+        });
+
+        it('should revert if spender has insufficient allowance', async () => {
+            const ownerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = ownerBalance;
+
+            const spenderAllowance = await token.allowance(owner, spender).callAsync();
+            const isSpenderAllowanceInsufficient = spenderAllowance.comparedTo(amountToTransfer) < 0;
+            expect(isSpenderAllowanceInsufficient).to.be.true();
+
+            return expect(
+                token.transferFrom(owner, spender, amountToTransfer).callAsync({
+                    from: spender,
+                }),
+            ).to.revertWith(RevertReason.Erc20InsufficientAllowance);
+        });
+
+        it('should return true on a 0 value transfer', async () => {
+            const amountToTransfer = new BigNumber(0);
+            const didReturnTrue = await token.transferFrom(owner, spender, amountToTransfer).callAsync({
+                from: spender,
+            });
+            expect(didReturnTrue).to.be.true();
+        });
+
+        it('should not modify spender allowance if spender allowance is 2^256 - 1', async () => {
+            const initOwnerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = initOwnerBalance;
+            const initSpenderAllowance = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.approve(spender, initSpenderAllowance).sendTransactionAsync({ from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.transferFrom(owner, spender, amountToTransfer).sendTransactionAsync({
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const newSpenderAllowance = await token.allowance(owner, spender).callAsync();
+            expect(initSpenderAllowance).to.be.bignumber.equal(newSpenderAllowance);
+        });
+
+        it('should transfer the correct balances if spender has sufficient allowance', async () => {
+            const initOwnerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = initOwnerBalance;
+            const initSpenderAllowance = initOwnerBalance;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.approve(spender, initSpenderAllowance).sendTransactionAsync({ from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.transferFrom(owner, spender, amountToTransfer).sendTransactionAsync({
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const newOwnerBalance = await token.balanceOf(owner).callAsync();
+            const newSpenderBalance = await token.balanceOf(spender).callAsync();
+
+            expect(newOwnerBalance).to.be.bignumber.equal(0);
+            expect(newSpenderBalance).to.be.bignumber.equal(initOwnerBalance);
+        });
+
+        it('should modify allowance if spender has sufficient allowance less than 2^256 - 1', async () => {
+            const initOwnerBalance = await token.balanceOf(owner).callAsync();
+            const amountToTransfer = initOwnerBalance;
+            const initSpenderAllowance = initOwnerBalance;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.approve(spender, initSpenderAllowance).sendTransactionAsync({ from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await token.transferFrom(owner, spender, amountToTransfer).sendTransactionAsync({
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const newSpenderAllowance = await token.allowance(owner, spender).callAsync();
+            expect(newSpenderAllowance).to.be.bignumber.equal(0);
+        });
+    });
+});
--- a/contracts/erc20/test/weth9.ts
+++ b/contracts/erc20/test/weth9.ts
@@ -0,0 +1,149 @@
+import {
+    chaiSetup,
+    constants,
+    expectInsufficientFundsAsync,
+    expectTransactionFailedWithoutReasonAsync,
+    provider,
+    txDefaults,
+    web3Wrapper,
+} from '@0x/contracts-test-utils';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+
+import { WETH9Contract } from './wrappers';
+
+import { artifacts } from './artifacts';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('EtherToken', () => {
+    let account: string;
+    const gasPrice = new BigNumber(constants.DEFAULT_GAS_PRICE);
+    let etherToken: WETH9Contract;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        account = accounts[0];
+
+        etherToken = await WETH9Contract.deployFrom0xArtifactAsync(
+            artifacts.WETH9,
+            provider,
+            {
+                ...txDefaults,
+                gasPrice,
+            },
+            artifacts,
+        );
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('deposit', () => {
+        it('should revert if caller attempts to deposit more Ether than caller balance', async () => {
+            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const ethToDeposit = initEthBalance.plus(1);
+
+            return expectInsufficientFundsAsync(etherToken.deposit().sendTransactionAsync({ value: ethToDeposit }));
+        });
+
+        it('should convert deposited Ether to wrapped Ether tokens', async () => {
+            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const initEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+
+            const ethToDeposit = new BigNumber(Web3Wrapper.toWei(new BigNumber(1)));
+
+            const txHash = await etherToken.deposit().sendTransactionAsync({ value: ethToDeposit });
+            const receipt = await web3Wrapper.awaitTransactionSuccessAsync(
+                txHash,
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const ethSpentOnGas = gasPrice.times(receipt.gasUsed);
+            const finalEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const finalEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+
+            expect(finalEthBalance).to.be.bignumber.equal(initEthBalance.minus(ethToDeposit.plus(ethSpentOnGas)));
+            expect(finalEthTokenBalance).to.be.bignumber.equal(initEthTokenBalance.plus(ethToDeposit));
+        });
+    });
+
+    describe('withdraw', () => {
+        it('should revert if caller attempts to withdraw greater than caller balance', async () => {
+            const initEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+            const ethTokensToWithdraw = initEthTokenBalance.plus(1);
+
+            return expectTransactionFailedWithoutReasonAsync(
+                etherToken.withdraw(ethTokensToWithdraw).sendTransactionAsync(),
+            );
+        });
+
+        it('should convert ether tokens to ether with sufficient balance', async () => {
+            const ethToDeposit = new BigNumber(Web3Wrapper.toWei(new BigNumber(1)));
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await etherToken.deposit().sendTransactionAsync({ value: ethToDeposit }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const initEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const ethTokensToWithdraw = initEthTokenBalance;
+            expect(ethTokensToWithdraw).to.not.be.bignumber.equal(0);
+            const txHash = await etherToken.withdraw(ethTokensToWithdraw).sendTransactionAsync({
+                gas: constants.MAX_ETHERTOKEN_WITHDRAW_GAS,
+            });
+            const receipt = await web3Wrapper.awaitTransactionSuccessAsync(
+                txHash,
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const ethSpentOnGas = gasPrice.times(receipt.gasUsed);
+            const finalEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const finalEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+
+            expect(finalEthBalance).to.be.bignumber.equal(
+                initEthBalance.plus(ethTokensToWithdraw.minus(ethSpentOnGas)),
+            );
+            expect(finalEthTokenBalance).to.be.bignumber.equal(initEthTokenBalance.minus(ethTokensToWithdraw));
+        });
+    });
+
+    describe('fallback', () => {
+        it('should convert sent ether to ether tokens', async () => {
+            const initEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const initEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+
+            const ethToDeposit = Web3Wrapper.toBaseUnitAmount(new BigNumber(1), 18);
+
+            const txHash = await web3Wrapper.sendTransactionAsync({
+                from: account,
+                to: etherToken.address,
+                value: ethToDeposit,
+                gasPrice,
+            });
+
+            const receipt = await web3Wrapper.awaitTransactionSuccessAsync(
+                txHash,
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const ethSpentOnGas = gasPrice.times(receipt.gasUsed);
+            const finalEthBalance = await web3Wrapper.getBalanceInWeiAsync(account);
+            const finalEthTokenBalance = await etherToken.balanceOf(account).callAsync();
+
+            expect(finalEthBalance).to.be.bignumber.equal(initEthBalance.minus(ethToDeposit.plus(ethSpentOnGas)));
+            expect(finalEthTokenBalance).to.be.bignumber.equal(initEthTokenBalance.plus(ethToDeposit));
+        });
+    });
+});
--- a/contracts/erc20/test/wrappers.ts
+++ b/contracts/erc20/test/wrappers.ts
@@ -0,0 +1,22 @@
+/*
+ * -----------------------------------------------------------------------------
+ * Warning: This file is auto-generated by contracts-gen. Don't edit manually.
+ * -----------------------------------------------------------------------------
+ */
+export * from '../test/generated-wrappers/dummy_erc20_token';
+export * from '../test/generated-wrappers/dummy_multiple_return_erc20_token';
+export * from '../test/generated-wrappers/dummy_no_return_erc20_token';
+export * from '../test/generated-wrappers/erc20_token';
+export * from '../test/generated-wrappers/i_erc20_token';
+export * from '../test/generated-wrappers/i_erc20_token_v06';
+export * from '../test/generated-wrappers/i_ether_token';
+export * from '../test/generated-wrappers/i_ether_token_v06';
+export * from '../test/generated-wrappers/lib_erc20_token';
+export * from '../test/generated-wrappers/lib_erc20_token_v06';
+export * from '../test/generated-wrappers/mintable_erc20_token';
+export * from '../test/generated-wrappers/test_lib_erc20_token';
+export * from '../test/generated-wrappers/test_lib_erc20_token_target';
+export * from '../test/generated-wrappers/unlimited_allowance_erc20_token';
+export * from '../test/generated-wrappers/untransferrable_dummy_erc20_token';
+export * from '../test/generated-wrappers/weth9';
+export * from '../test/generated-wrappers/zrx_token';
--- a/contracts/erc20/test/zrx_token.ts
+++ b/contracts/erc20/test/zrx_token.ts
@@ -0,0 +1,210 @@
+import { chaiSetup, constants, provider, txDefaults, web3Wrapper } from '@0x/contracts-test-utils';
+import { BlockchainLifecycle } from '@0x/dev-utils';
+import { BigNumber } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import * as chai from 'chai';
+
+import { ZRXTokenContract } from './wrappers';
+
+import { artifacts } from './artifacts';
+
+chaiSetup.configure();
+const expect = chai.expect;
+const blockchainLifecycle = new BlockchainLifecycle(web3Wrapper);
+
+describe('ZRXToken', () => {
+    let owner: string;
+    let spender: string;
+    let MAX_UINT: BigNumber;
+    let zrxToken: ZRXTokenContract;
+
+    before(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    after(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    before(async () => {
+        const accounts = await web3Wrapper.getAvailableAddressesAsync();
+        owner = accounts[0];
+        spender = accounts[1];
+        zrxToken = await ZRXTokenContract.deployFrom0xArtifactAsync(
+            artifacts.ZRXToken,
+            provider,
+            txDefaults,
+            artifacts,
+        );
+        MAX_UINT = constants.UNLIMITED_ALLOWANCE_IN_BASE_UNITS;
+    });
+    beforeEach(async () => {
+        await blockchainLifecycle.startAsync();
+    });
+    afterEach(async () => {
+        await blockchainLifecycle.revertAsync();
+    });
+    describe('constants', () => {
+        it('should have 18 decimals', async () => {
+            const decimals = new BigNumber(await zrxToken.decimals().callAsync());
+            const expectedDecimals = 18;
+            expect(decimals).to.be.bignumber.equal(expectedDecimals);
+        });
+
+        it('should have a total supply of 1 billion tokens', async () => {
+            const totalSupply = new BigNumber(await zrxToken.totalSupply().callAsync());
+            const expectedTotalSupply = 1000000000;
+            expect(Web3Wrapper.toUnitAmount(totalSupply, 18)).to.be.bignumber.equal(expectedTotalSupply);
+        });
+
+        it('should be named 0x Protocol Token', async () => {
+            const name = await zrxToken.name().callAsync();
+            const expectedName = '0x Protocol Token';
+            expect(name).to.be.equal(expectedName);
+        });
+
+        it('should have the symbol ZRX', async () => {
+            const symbol = await zrxToken.symbol().callAsync();
+            const expectedSymbol = 'ZRX';
+            expect(symbol).to.be.equal(expectedSymbol);
+        });
+    });
+
+    describe('constructor', () => {
+        it('should initialize owner balance to totalSupply', async () => {
+            const ownerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const totalSupply = new BigNumber(await zrxToken.totalSupply().callAsync());
+            expect(totalSupply).to.be.bignumber.equal(ownerBalance);
+        });
+    });
+
+    describe('transfer', () => {
+        it('should transfer balance from sender to receiver', async () => {
+            const receiver = spender;
+            const initOwnerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const amountToTransfer = new BigNumber(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transfer(receiver, amountToTransfer).sendTransactionAsync({ from: owner }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const finalOwnerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const finalReceiverBalance = await zrxToken.balanceOf(receiver).callAsync();
+
+            const expectedFinalOwnerBalance = initOwnerBalance.minus(amountToTransfer);
+            const expectedFinalReceiverBalance = amountToTransfer;
+            expect(finalOwnerBalance).to.be.bignumber.equal(expectedFinalOwnerBalance);
+            expect(finalReceiverBalance).to.be.bignumber.equal(expectedFinalReceiverBalance);
+        });
+
+        it('should return true on a 0 value transfer', async () => {
+            const didReturnTrue = await zrxToken.transfer(spender, new BigNumber(0)).callAsync({
+                from: owner,
+            });
+            expect(didReturnTrue).to.be.true();
+        });
+    });
+
+    describe('transferFrom', () => {
+        it('should return false if owner has insufficient balance', async () => {
+            const ownerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const amountToTransfer = ownerBalance.plus(1);
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve(spender, amountToTransfer).sendTransactionAsync({
+                    from: owner,
+                    gas: constants.MAX_TOKEN_APPROVE_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            const didReturnTrue = await zrxToken.transferFrom(owner, spender, amountToTransfer).callAsync({
+                from: spender,
+            });
+            expect(didReturnTrue).to.be.false();
+        });
+
+        it('should return false if spender has insufficient allowance', async () => {
+            const ownerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const amountToTransfer = ownerBalance;
+
+            const spenderAllowance = await zrxToken.allowance(owner, spender).callAsync();
+            const isSpenderAllowanceInsufficient = spenderAllowance.comparedTo(amountToTransfer) < 0;
+            expect(isSpenderAllowanceInsufficient).to.be.true();
+
+            const didReturnTrue = await zrxToken.transferFrom(owner, spender, amountToTransfer).callAsync({
+                from: spender,
+            });
+            expect(didReturnTrue).to.be.false();
+        });
+
+        it('should return true on a 0 value transfer', async () => {
+            const amountToTransfer = new BigNumber(0);
+            const didReturnTrue = await zrxToken.transferFrom(owner, spender, amountToTransfer).callAsync({
+                from: spender,
+            });
+            expect(didReturnTrue).to.be.true();
+        });
+
+        it('should not modify spender allowance if spender allowance is 2^256 - 1', async () => {
+            const initOwnerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const amountToTransfer = initOwnerBalance;
+            const initSpenderAllowance = MAX_UINT;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve(spender, initSpenderAllowance).sendTransactionAsync({
+                    from: owner,
+                    gas: constants.MAX_TOKEN_APPROVE_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transferFrom(owner, spender, amountToTransfer).sendTransactionAsync({
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const newSpenderAllowance = await zrxToken.allowance(owner, spender).callAsync();
+            expect(initSpenderAllowance).to.be.bignumber.equal(newSpenderAllowance);
+        });
+
+        it('should transfer the correct balances if spender has sufficient allowance', async () => {
+            const initOwnerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const initSpenderBalance = await zrxToken.balanceOf(spender).callAsync();
+            const amountToTransfer = initOwnerBalance;
+            const initSpenderAllowance = initOwnerBalance;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve(spender, initSpenderAllowance).sendTransactionAsync(),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transferFrom(owner, spender, amountToTransfer).sendTransactionAsync({
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const newOwnerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const newSpenderBalance = await zrxToken.balanceOf(spender).callAsync();
+
+            expect(newOwnerBalance).to.be.bignumber.equal(0);
+            expect(newSpenderBalance).to.be.bignumber.equal(initSpenderBalance.plus(initOwnerBalance));
+        });
+
+        it('should modify allowance if spender has sufficient allowance less than 2^256 - 1', async () => {
+            const initOwnerBalance = await zrxToken.balanceOf(owner).callAsync();
+            const amountToTransfer = initOwnerBalance;
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.approve(spender, amountToTransfer).sendTransactionAsync(),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+            await web3Wrapper.awaitTransactionSuccessAsync(
+                await zrxToken.transferFrom(owner, spender, amountToTransfer).sendTransactionAsync({
+                    from: spender,
+                    gas: constants.MAX_TOKEN_TRANSFERFROM_GAS,
+                }),
+                constants.AWAIT_TRANSACTION_MINED_MS,
+            );
+
+            const newSpenderAllowance = await zrxToken.allowance(owner, spender).callAsync();
+            expect(newSpenderAllowance).to.be.bignumber.equal(0);
+        });
+    });
+});
--- a/contracts/erc20/truffle-config.js
+++ b/contracts/erc20/truffle-config.js
@@ -0,0 +1,96 @@
+/**
+ * Use this file to configure your truffle project. It's seeded with some
+ * common settings for different networks and features like migrations,
+ * compilation and testing. Uncomment the ones you need or modify
+ * them to suit your project as necessary.
+ *
+ * More information about configuration can be found at:
+ *
+ * truffleframework.com/docs/advanced/configuration
+ *
+ * To deploy via Infura you'll need a wallet provider (like truffle-hdwallet-provider)
+ * to sign your transactions before they're sent to a remote public node. Infura accounts
+ * are available for free at: infura.io/register.
+ *
+ * You'll also need a mnemonic - the twelve word phrase the wallet uses to generate
+ * public/private key pairs. If you're publishing your code to GitHub make sure you load this
+ * phrase from a file you've .gitignored so it doesn't accidentally become public.
+ *
+ */
+
+// const HDWalletProvider = require('truffle-hdwallet-provider');
+// const infuraKey = "fj4jll3k.....";
+//
+// const fs = require('fs');
+// const mnemonic = fs.readFileSync(".secret").toString().trim();
+
+module.exports = {
+    /**
+     * Networks define how you connect to your ethereum client and let you set the
+     * defaults web3 uses to send transactions. If you don't specify one truffle
+     * will spin up a development blockchain for you on port 9545 when you
+     * run `develop` or `test`. You can ask a truffle command to use a specific
+     * network from the command line, e.g
+     *
+     * $ truffle test --network <network-name>
+     */
+
+    networks: {
+        // Useful for testing. The `development` name is special - truffle uses it by default
+        // if it's defined here and no other network is specified at the command line.
+        // You should run a client (like ganache-cli, geth or parity) in a separate terminal
+        // tab if you use this network and you must also set the `host`, `port` and `network_id`
+        // options below to some value.
+        //
+        // development: {
+        //  host: "127.0.0.1",     // Localhost (default: none)
+        //  port: 8545,            // Standard Ethereum port (default: none)
+        //  network_id: "*",       // Any network (default: none)
+        // },
+        // Another network with more advanced options...
+        // advanced: {
+        // port: 8777,             // Custom port
+        // network_id: 1342,       // Custom network
+        // gas: 8500000,           // Gas sent with each transaction (default: ~6700000)
+        // gasPrice: 20000000000,  // 20 gwei (in wei) (default: 100 gwei)
+        // from: <address>,        // Account to send txs from (default: accounts[0])
+        // websockets: true        // Enable EventEmitter interface for web3 (default: false)
+        // },
+        // Useful for deploying to a public network.
+        // NB: It's important to wrap the provider as a function.
+        // ropsten: {
+        // provider: () => new HDWalletProvider(mnemonic, `https://ropsten.infura.io/v3/YOUR-PROJECT-ID`),
+        // network_id: 3,       // Ropsten's id
+        // gas: 5500000,        // Ropsten has a lower block limit than mainnet
+        // confirmations: 2,    // # of confs to wait between deployments. (default: 0)
+        // timeoutBlocks: 200,  // # of blocks before a deployment times out  (minimum/default: 50)
+        // skipDryRun: true     // Skip dry run before migrations? (default: false for public nets )
+        // },
+        // Useful for private networks
+        // private: {
+        // provider: () => new HDWalletProvider(mnemonic, `https://network.io`),
+        // network_id: 2111,   // This network is yours, in the cloud.
+        // production: true    // Treats this network as if it was a public net. (default: false)
+        // }
+    },
+
+    // Set default mocha options here, use special reporters etc.
+    mocha: {
+        // timeout: 100000
+    },
+
+    // Configure your compilers
+    compilers: {
+        solc: {
+            version: '0.5.9',
+            settings: {
+                evmVersion: 'constantinople',
+                optimizer: {
+                    enabled: true,
+                    runs: 1000000,
+                    details: { yul: true, deduplicate: true, cse: true, constantOptimizer: true },
+                },
+            },
+        },
+    },
+};
--- a/contracts/erc20/tsconfig.json
+++ b/contracts/erc20/tsconfig.json
@@ -0,0 +1,31 @@
+{
+    "extends": "../../tsconfig",
+    "compilerOptions": { "outDir": "lib", "rootDir": ".", "resolveJsonModule": true },
+    "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
+    "files": [
+        "generated-artifacts/DummyERC20Token.json",
+        "generated-artifacts/DummyMultipleReturnERC20Token.json",
+        "generated-artifacts/DummyNoReturnERC20Token.json",
+        "generated-artifacts/ERC20Token.json",
+        "generated-artifacts/WETH9.json",
+        "generated-artifacts/ZRXToken.json",
+        "test/generated-artifacts/DummyERC20Token.json",
+        "test/generated-artifacts/DummyMultipleReturnERC20Token.json",
+        "test/generated-artifacts/DummyNoReturnERC20Token.json",
+        "test/generated-artifacts/ERC20Token.json",
+        "test/generated-artifacts/IERC20Token.json",
+        "test/generated-artifacts/IERC20TokenV06.json",
+        "test/generated-artifacts/IEtherToken.json",
+        "test/generated-artifacts/IEtherTokenV06.json",
+        "test/generated-artifacts/LibERC20Token.json",
+        "test/generated-artifacts/LibERC20TokenV06.json",
+        "test/generated-artifacts/MintableERC20Token.json",
+        "test/generated-artifacts/TestLibERC20Token.json",
+        "test/generated-artifacts/TestLibERC20TokenTarget.json",
+        "test/generated-artifacts/UnlimitedAllowanceERC20Token.json",
+        "test/generated-artifacts/UntransferrableDummyERC20Token.json",
+        "test/generated-artifacts/WETH9.json",
+        "test/generated-artifacts/ZRXToken.json"
+    ],
+    "exclude": ["./deploy/solc/solc_bin"]
+}
--- a/contracts/examples/tslint.json
+++ b/contracts/examples/tslint.json
--- a/packages/asset-buyer/typedoc-tsconfig.json
+++ b/packages/asset-buyer/typedoc-tsconfig.json
--- a/contracts/examples/CHANGELOG.json
+++ b/contracts/examples/CHANGELOG.json
@@ -1,29 +0,0 @@
-[
-    {
-        "timestamp": 1547225310,
-        "version": "1.0.4",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "timestamp": 1547040760,
-        "version": "1.0.3",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "timestamp": 1544741676,
-        "version": "1.0.2",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    }
-]
--- a/contracts/examples/CHANGELOG.md
+++ b/contracts/examples/CHANGELOG.md
@@ -1,18 +0,0 @@
-<!--
-changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
-Edit the package's CHANGELOG.json file only.
-->
-
-CHANGELOG
-
-## v1.0.4 - _January 11, 2019_
-
-    * Dependencies updated
-
-## v1.0.3 - _January 9, 2019_
-
-    * Dependencies updated
-
-## v1.0.2 - _December 13, 2018_
-
-    * Dependencies updated
--- a/contracts/examples/README.md
+++ b/contracts/examples/README.md
@@ -1,56 +0,0 @@
-## Contract examples
-
-Example smart contracts that interact with 0x protocol.
-
-## Usage
-
-Contracts can be found in the [contracts](./contracts) directory.
-This package contains example implementations of contracts that interact with the protocol but are _not_ intended for use in production. Examples include [filter](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#filter-contracts) contracts, a [Wallet](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#wallet) contract, and a [Validator](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/v2-specification.md#validator) contract, among others.
-
-## Contributing
-
-We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
-
-For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
-
-Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
-
-### Install Dependencies
-
-If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
-
-```bash
-yarn config set workspaces-experimental true
-```
-
-Then install dependencies
-
-```bash
-yarn install
-```
-
-### Build
-
-To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
-
-```bash
-PKG=@0x/contracts-examples yarn build
-```
-
-Or continuously rebuild on change:
-
-```bash
-PKG=@0x/contracts-examples yarn watch
-```
-
-### Clean
-
-```bash
-yarn clean
-```
-
-### Lint
-
-```bash
-yarn lint
-```
--- a/contracts/examples/compiler.json
+++ b/contracts/examples/compiler.json
@@ -1,22 +0,0 @@
-{
-    "artifactsDir": "./generated-artifacts",
-    "contractsDir": "./contracts",
-    "compilerSettings": {
-        "optimizer": {
-            "enabled": true,
-            "runs": 1000000
-        },
-        "outputSelection": {
-            "*": {
-                "*": [
-                    "abi",
-                    "evm.bytecode.object",
-                    "evm.bytecode.sourceMap",
-                    "evm.deployedBytecode.object",
-                    "evm.deployedBytecode.sourceMap"
-                ]
-            }
-        }
-    },
-    "contracts": ["ExchangeWrapper", "Validator", "Wallet", "Whitelist"]
-}
--- a/contracts/examples/contracts/ExchangeWrapper/ExchangeWrapper.sol
+++ b/contracts/examples/contracts/ExchangeWrapper/ExchangeWrapper.sol
@@ -1,100 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-
-
-contract ExchangeWrapper {
-
-    // Exchange contract.
-    // solhint-disable-next-line var-name-mixedcase
-    IExchange internal EXCHANGE;
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-    }
-
-    /// @dev Cancels all orders created by sender with a salt less than or equal to the targetOrderEpoch
-    ///      and senderAddress equal to this contract.
-    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param makerSignature Proof that maker wishes to call this function with given params.
-    function cancelOrdersUpTo(
-        uint256 targetOrderEpoch,
-        uint256 salt,
-        bytes makerSignature
-    )
-        external
-    {
-        address makerAddress = msg.sender;
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.cancelOrdersUpTo.selector,
-            targetOrderEpoch
-        );
-
-        // Call `cancelOrdersUpTo` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            makerAddress,
-            data,
-            makerSignature
-        );
-    }
-
-    /// @dev Fills an order using `msg.sender` as the taker.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param orderSignature Proof that order has been created by maker.
-    /// @param takerSignature Proof that taker wishes to call this function with given params.
-    function fillOrder(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        uint256 salt,
-        bytes memory orderSignature,
-        bytes memory takerSignature
-    )
-        public
-    {
-        address takerAddress = msg.sender;
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.fillOrder.selector,
-            order,
-            takerAssetFillAmount,
-            orderSignature
-        );
-
-        // Call `fillOrder` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            takerAddress,
-            data,
-            takerSignature
-        );
-    }
-}
--- a/contracts/examples/contracts/Validator/Validator.sol
+++ b/contracts/examples/contracts/Validator/Validator.sol
@@ -1,56 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IValidator.sol";
-
-
-contract Validator is 
-    IValidator
-{
-
-    // The single valid signer for this wallet.
-    // solhint-disable-next-line var-name-mixedcase
-    address internal VALID_SIGNER;
-
-    /// @dev constructs a new `Validator` with a single valid signer.
-    /// @param validSigner The sole, valid signer.
-    constructor (address validSigner) public {
-        VALID_SIGNER = validSigner;
-    }
-
-    /// @dev Verifies that a signature is valid. `signer` must match `VALID_SIGNER`.
-    /// @param hash Message hash that is signed.
-    /// @param signerAddress Address that should have signed the given hash.
-    /// @param signature Proof of signing.
-    /// @return Validity of signature.
-    // solhint-disable no-unused-vars
-    function isValidSignature(
-        bytes32 hash,
-        address signerAddress,
-        bytes signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        return (signerAddress == VALID_SIGNER);
-    }
-    // solhint-enable no-unused-vars
-}
--- a/contracts/examples/contracts/Wallet/Wallet.sol
+++ b/contracts/examples/contracts/Wallet/Wallet.sol
@@ -1,65 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IWallet.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-
-
-contract Wallet is 
-    IWallet
-{
-    using LibBytes for bytes;
-
-    // The owner of this wallet.
-    // solhint-disable-next-line var-name-mixedcase
-    address internal WALLET_OWNER;
-
-    /// @dev constructs a new `Wallet` with a single owner.
-    /// @param walletOwner The owner of this wallet.
-    constructor (address walletOwner) public {
-        WALLET_OWNER = walletOwner;
-    }
-
-    /// @dev Validates an EIP712 signature.
-    ///      The signer must match the owner of this wallet.
-    /// @param hash Message hash that is signed.
-    /// @param eip712Signature Proof of signing.
-    /// @return Validity of signature.
-    function isValidSignature(
-        bytes32 hash,
-        bytes eip712Signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        require(
-            eip712Signature.length == 65,
-            "LENGTH_65_REQUIRED"
-        );
-
-        uint8 v = uint8(eip712Signature[0]);
-        bytes32 r = eip712Signature.readBytes32(1);
-        bytes32 s = eip712Signature.readBytes32(33);
-        address recoveredAddress = ecrecover(hash, v, r, s);
-        isValid = WALLET_OWNER == recoveredAddress;
-        return isValid;
-    }
-}
--- a/contracts/examples/contracts/Whitelist/Whitelist.sol
+++ b/contracts/examples/contracts/Whitelist/Whitelist.sol
@@ -1,136 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-
-
-contract Whitelist is
-    Ownable
-{
-
-    // Mapping of address => whitelist status.
-    mapping (address => bool) public isWhitelisted;
-
-    // Exchange contract.
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    bytes internal TX_ORIGIN_SIGNATURE;
-    // solhint-enable var-name-mixedcase
-
-    byte constant internal VALIDATOR_SIGNATURE_BYTE = "\x05";
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-        TX_ORIGIN_SIGNATURE = abi.encodePacked(address(this), VALIDATOR_SIGNATURE_BYTE);
-    }
-
-    /// @dev Adds or removes an address from the whitelist.
-    /// @param target Address to add or remove from whitelist.
-    /// @param isApproved Whitelist status to assign to address.
-    function updateWhitelistStatus(
-        address target,
-        bool isApproved
-    )
-        external
-        onlyOwner
-    {
-        isWhitelisted[target] = isApproved;
-    }
-
-    /// @dev Verifies signer is same as signer of current Ethereum transaction.
-    ///      NOTE: This function can currently be used to validate signatures coming from outside of this contract.
-    ///      Extra safety checks can be added for a production contract.
-    /// @param signerAddress Address that should have signed the given hash.
-    /// @param signature Proof of signing.
-    /// @return Validity of order signature.
-    // solhint-disable no-unused-vars
-    function isValidSignature(
-        bytes32 hash,
-        address signerAddress,
-        bytes signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        // solhint-disable-next-line avoid-tx-origin
-        return signerAddress == tx.origin;
-    }
-    // solhint-enable no-unused-vars
-
-    /// @dev Fills an order using `msg.sender` as the taker.
-    ///      The transaction will revert if both the maker and taker are not whitelisted.
-    ///      Orders should specify this contract as the `senderAddress` in order to gaurantee
-    ///      that both maker and taker have been whitelisted.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param orderSignature Proof that order has been created by maker.
-    function fillOrderIfWhitelisted(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        uint256 salt,
-        bytes memory orderSignature
-    )
-        public
-    {
-        address takerAddress = msg.sender;
-
-        // This contract must be the entry point for the transaction.
-        require(
-            // solhint-disable-next-line avoid-tx-origin
-            takerAddress == tx.origin,
-            "INVALID_SENDER"
-        );
-
-        // Check if maker is on the whitelist.
-        require(
-            isWhitelisted[order.makerAddress],
-            "MAKER_NOT_WHITELISTED"
-        );
-
-        // Check if taker is on the whitelist.
-        require(
-            isWhitelisted[takerAddress],
-            "TAKER_NOT_WHITELISTED"
-        );
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.fillOrder.selector,
-            order,
-            takerAssetFillAmount,
-            orderSignature
-        );
-
-        // Call `fillOrder` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            takerAddress,
-            data,
-            TX_ORIGIN_SIGNATURE
-        );
-    }
-}
--- a/contracts/examples/package.json
+++ b/contracts/examples/package.json
@@ -1,81 +0,0 @@
-{
-    "name": "@0x/contracts-examples",
-    "version": "1.0.4",
-    "engines": {
-        "node": ">=6.12"
-    },
-    "description": "Smart contract examples of 0x protocol",
-    "main": "lib/src/index.js",
-    "directories": {
-        "test": "test"
-    },
-    "scripts": {
-        "build": "yarn pre_build && tsc -b",
-        "build:ci": "yarn build",
-        "pre_build": "run-s compile generate_contract_wrappers",
-        "compile": "sol-compiler",
-        "watch": "sol-compiler -w",
-        "clean": "shx rm -rf lib generated-artifacts generated-wrappers",
-        "generate_contract_wrappers": "abi-gen --abis  ${npm_package_config_abis} --template ../../node_modules/@0x/abi-gen-templates/contract.handlebars --partials '../../node_modules/@0x/abi-gen-templates/partials/**/*.handlebars' --output generated-wrappers --backend ethers",
-        "lint": "tslint --format stylish --project . --exclude ./generated-wrappers/**/* --exclude ./generated-artifacts/**/* --exclude **/lib/**/* && yarn lint-contracts",
-        "lint-contracts": "solhint -c ../.solhint.json contracts/**/**/**/**/*.sol"
-    },
-    "config": {
-        "abis": "generated-artifacts/@(ExchangeWrapper|Validator|Wallet|Whitelist).json"
-    },
-    "repository": {
-        "type": "git",
-        "url": "https://github.com/0xProject/0x-monorepo.git"
-    },
-    "license": "Apache-2.0",
-    "bugs": {
-        "url": "https://github.com/0xProject/0x-monorepo/issues"
-    },
-    "homepage": "https://github.com/0xProject/0x-monorepo/contracts/examples/README.md",
-    "devDependencies": {
-        "@0x/abi-gen": "^1.0.21",
-        "@0x/contracts-test-utils": "^1.0.4",
-        "@0x/dev-utils": "^1.0.23",
-        "@0x/sol-compiler": "^2.0.1",
-        "@0x/subproviders": "^2.1.10",
-        "@0x/tslint-config": "^2.0.1",
-        "@types/bn.js": "^4.11.0",
-        "@types/lodash": "4.14.104",
-        "@types/node": "*",
-        "@types/yargs": "^10.0.0",
-        "chai": "^4.0.1",
-        "chai-as-promised": "^7.1.0",
-        "chai-bignumber": "^2.0.1",
-        "dirty-chai": "^2.0.1",
-        "ethereumjs-abi": "0.6.5",
-        "make-promises-safe": "^1.1.0",
-        "mocha": "^4.1.0",
-        "npm-run-all": "^4.1.2",
-        "shx": "^0.2.2",
-        "solhint": "^1.4.1",
-        "tslint": "5.11.0",
-        "typescript": "3.0.1",
-        "yargs": "^10.0.3"
-    },
-    "dependencies": {
-        "@0x/base-contract": "^3.0.12",
-        "@0x/contracts-interfaces": "^1.0.4",
-        "@0x/contracts-libs": "^1.0.4",
-        "@0x/contracts-multisig": "^1.0.4",
-        "@0x/contracts-tokens": "^1.0.4",
-        "@0x/contracts-utils": "^1.0.4",
-        "@0x/order-utils": "^3.1.1",
-        "@0x/types": "^1.5.1",
-        "@0x/typescript-typings": "^3.0.7",
-        "@0x/utils": "^3.0.0",
-        "@0x/web3-wrapper": "^3.2.3",
-        "@types/js-combinatorics": "^0.5.29",
-        "bn.js": "^4.11.8",
-        "ethereum-types": "^1.1.5",
-        "ethereumjs-util": "^5.1.1",
-        "lodash": "^4.17.5"
-    },
-    "publishConfig": {
-        "access": "public"
-    }
-}
--- a/contracts/examples/src/artifacts/index.ts
+++ b/contracts/examples/src/artifacts/index.ts
@@ -1,13 +0,0 @@
-import { ContractArtifact } from 'ethereum-types';
-
-import * as ExchangeWrapper from '../../generated-artifacts/ExchangeWrapper.json';
-import * as Validator from '../../generated-artifacts/Validator.json';
-import * as Wallet from '../../generated-artifacts/Wallet.json';
-import * as Whitelist from '../../generated-artifacts/Whitelist.json';
-
-export const artifacts = {
-    ExchangeWrapper: ExchangeWrapper as ContractArtifact,
-    Validator: Validator as ContractArtifact,
-    Wallet: Wallet as ContractArtifact,
-    Whitelist: Whitelist as ContractArtifact,
-};
--- a/contracts/examples/src/index.ts
+++ b/contracts/examples/src/index.ts
@@ -1,2 +0,0 @@
-export * from './artifacts';
-export * from './wrappers';
--- a/contracts/examples/src/wrappers/index.ts
+++ b/contracts/examples/src/wrappers/index.ts
@@ -1,4 +0,0 @@
-export * from '../../generated-wrappers/exchange_wrapper';
-export * from '../../generated-wrappers/validator';
-export * from '../../generated-wrappers/wallet';
-export * from '../../generated-wrappers/whitelist';
--- a/contracts/examples/tsconfig.json
+++ b/contracts/examples/tsconfig.json
@@ -1,16 +0,0 @@
-{
-    "extends": "../../tsconfig",
-    "compilerOptions": {
-        "outDir": "lib",
-        "rootDir": ".",
-        "resolveJsonModule": true
-    },
-    "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
-    "files": [
-        "./generated-artifacts/ExchangeWrapper.json",
-        "./generated-artifacts/Validator.json",
-        "./generated-artifacts/Wallet.json",
-        "./generated-artifacts/Whitelist.json"
-    ],
-    "exclude": ["./deploy/solc/solc_bin"]
-}
--- a/contracts/extensions/CHANGELOG.json
+++ b/contracts/extensions/CHANGELOG.json
@@ -1,47 +0,0 @@
-[
-    {
-        "timestamp": 1547225310,
-        "version": "1.2.1",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    },
-    {
-        "version": "1.2.0",
-        "changes": [
-            {
-                "note": "Added Dutch Auction Wrapper",
-                "pr": 1465
-            }
-        ],
-        "timestamp": 1547040760
-    },
-    {
-        "version": "1.1.0",
-        "changes": [
-            {
-                "note": "Added Balance Threshold Filter",
-                "pr": 1383
-            },
-            {
-                "note": "Add OrderMatcher",
-                "pr": 1117
-            },
-            {
-                "note": "Add OrderValidator",
-                "pr": 1464
-            }
-        ]
-    },
-    {
-        "timestamp": 1544741676,
-        "version": "1.0.2",
-        "changes": [
-            {
-                "note": "Dependencies updated"
-            }
-        ]
-    }
-]
--- a/contracts/extensions/CHANGELOG.md
+++ b/contracts/extensions/CHANGELOG.md
@@ -1,24 +0,0 @@
-<!--
-changelogUtils.file is auto-generated using the monorepo-scripts package. Don't edit directly.
-Edit the package's CHANGELOG.json file only.
-->
-
-CHANGELOG
-
-## v1.2.1 - _January 11, 2019_
-
-    * Dependencies updated
-
-## v1.2.0 - _January 9, 2019_
-
-    * Added Dutch Auction Wrapper (#1465)
-
-## v1.1.0 - _Invalid date_
-
-    * Added Balance Threshold Filter (#1383)
-    * Add OrderMatcher (#1117)
-    * Add OrderValidator (#1464)
-
-## v1.0.2 - _December 13, 2018_
-
-    * Dependencies updated
--- a/contracts/extensions/DEPLOYS.json
+++ b/contracts/extensions/DEPLOYS.json
@@ -1,31 +0,0 @@
-[
-    {
-        "name": "Forwarder",
-        "version": "1.1.0",
-        "changes": [
-            {
-                "note": "Round up when calculating remaining amounts in marketBuy functions",
-                "pr": 1162,
-                "networks": {
-                    "1": "0x5468a1dc173652ee28d249c271fa9933144746b1",
-                    "3": "0x2240dab907db71e64d3e0dba4800c83b5c502d4e",
-                    "42": "0x17992e4ffb22730138e4b62aaa6367fa9d3699a6"
-                }
-            }
-        ]
-    },
-    {
-        "name": "Forwarder",
-        "version": "1.0.0",
-        "changes": [
-            {
-                "note": "protocol v2 deploy",
-                "networks": {
-                    "1": "0x7afc2d5107af94c462a194d2c21b5bdd238709d6",
-                    "3": "0x3983e204b12b3c02fb0638caf2cd406a62e0ead3",
-                    "42": "0xd85e2fa7e7e252b27b01bf0d65c946959d2f45b8"
-                }
-            }
-        ]
-    }
-]
--- a/contracts/extensions/README.md
+++ b/contracts/extensions/README.md
@@ -1,69 +0,0 @@
-## Contract extensions
-
-Smart contracts that implement extensions for the 0x protocol.
-
-## Usage
-
-Contract extensions of the protocol can be found in the [contracts](./contracts) directory. This directory contains contracts that interact with the 2.0.0 contracts and will be used in production, such as the [Forwarder](https://github.com/0xProject/0x-protocol-specification/blob/master/v2/forwarder-specification.md) contract.
-
-## Bug bounty
-
-A bug bounty for the 2.0.0 contracts is ongoing! Instructions can be found [here](https://0xproject.com/wiki#Bug-Bounty).
-
-## Contributing
-
-We strongly recommend that the community help us make improvements and determine the future direction of the protocol. To report bugs within this package, please create an issue in this repository.
-
-For proposals regarding the 0x protocol's smart contract architecture, message format, or additional functionality, go to the [0x Improvement Proposals (ZEIPs)](https://github.com/0xProject/ZEIPs) repository and follow the contribution guidelines provided therein.
-
-Please read our [contribution guidelines](../../CONTRIBUTING.md) before getting started.
-
-### Install Dependencies
-
-If you don't have yarn workspaces enabled (Yarn < v1.0) - enable them:
-
-```bash
-yarn config set workspaces-experimental true
-```
-
-Then install dependencies
-
-```bash
-yarn install
-```
-
-### Build
-
-To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
-
-```bash
-PKG=@0x/contracts-extensions yarn build
-```
-
-Or continuously rebuild on change:
-
-```bash
-PKG=@0x/contracts-extensions yarn watch
-```
-
-### Clean
-
-```bash
-yarn clean
-```
-
-### Lint
-
-```bash
-yarn lint
-```
-
-### Run Tests
-
-```bash
-yarn test
-```
-
-#### Testing options
-
-Contracts testing options like coverage, profiling, revert traces or backing node choosing - are described [here](../TESTING.md).
--- a/contracts/extensions/compiler.json
+++ b/contracts/extensions/compiler.json
@@ -1,22 +0,0 @@
-{
-    "artifactsDir": "./generated-artifacts",
-    "contractsDir": "./contracts",
-    "compilerSettings": {
-        "optimizer": {
-            "enabled": true,
-            "runs": 1000000
-        },
-        "outputSelection": {
-            "*": {
-                "*": [
-                    "abi",
-                    "evm.bytecode.object",
-                    "evm.bytecode.sourceMap",
-                    "evm.deployedBytecode.object",
-                    "evm.deployedBytecode.sourceMap"
-                ]
-            }
-        }
-    },
-    "contracts": ["BalanceThresholdFilter", "DutchAuction", "Forwarder", "OrderMatcher", "OrderValidator"]
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/BalanceThresholdFilter.sol
@@ -1,45 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "./interfaces/IThresholdAsset.sol";
-import "./MixinBalanceThresholdFilterCore.sol";
-
-
-contract BalanceThresholdFilter is
-    MixinBalanceThresholdFilterCore
-{
-
-    /// @dev Constructs BalanceThresholdFilter.
-    /// @param exchange Address of 0x exchange.
-    /// @param thresholdAsset The asset that must be held by makers/takers.
-    /// @param balanceThreshold The minimum balance of `thresholdAsset` that must be held by makers/takers.
-    constructor(
-        address exchange,
-        address thresholdAsset,
-        uint256 balanceThreshold
-    )
-        public
-    {
-        EXCHANGE = IExchange(exchange);
-        THRESHOLD_ASSET = IThresholdAsset(thresholdAsset);
-        BALANCE_THRESHOLD = balanceThreshold;
-    }
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/MixinBalanceThresholdFilterCore.sol
@@ -1,135 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-libs/contracts/libs/LibExchangeSelectors.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "./mixins/MBalanceThresholdFilterCore.sol";
-import "./MixinExchangeCalldata.sol";
-
-
-contract MixinBalanceThresholdFilterCore is
-    MBalanceThresholdFilterCore,
-    MixinExchangeCalldata,
-    LibOrder,
-    LibExchangeSelectors
-{
-
-    /// @dev Executes an Exchange transaction iff the maker and taker meet 
-    ///      the hold at least `BALANCE_THRESHOLD` of the asset `THRESHOLD_ASSET` OR 
-    ///      the exchange function is a cancellation.
-    ///      Supported Exchange functions:
-    ///          batchFillOrders
-    ///          batchFillOrdersNoThrow
-    ///          batchFillOrKillOrders
-    ///          fillOrder
-    ///          fillOrderNoThrow
-    ///          fillOrKillOrder
-    ///          marketBuyOrders
-    ///          marketBuyOrdersNoThrow
-    ///          marketSellOrders
-    ///          marketSellOrdersNoThrow
-    ///          matchOrders
-    ///          cancelOrder
-    ///          batchCancelOrders
-    ///          cancelOrdersUpTo
-    ///     Trying to call any other exchange function will throw.
-    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
-    /// @param signerAddress Address of transaction signer.
-    /// @param signedExchangeTransaction AbiV2 encoded calldata.
-    /// @param signature Proof of signer transaction by signer.
-    function executeTransaction(
-        uint256 salt,
-        address signerAddress,
-        bytes signedExchangeTransaction,
-        bytes signature
-    ) 
-        external
-    {
-        // Get accounts whose balances must be validated
-        address[] memory addressesToValidate = getAddressesToValidate(signerAddress);
-
-        // Validate account balances
-        uint256 balanceThreshold = BALANCE_THRESHOLD;
-        IThresholdAsset thresholdAsset = THRESHOLD_ASSET;
-        for (uint256 i = 0; i < addressesToValidate.length; ++i) {
-            uint256 addressBalance = thresholdAsset.balanceOf(addressesToValidate[i]);
-            require(
-                addressBalance >= balanceThreshold,
-                "AT_LEAST_ONE_ADDRESS_DOES_NOT_MEET_BALANCE_THRESHOLD"
-            );
-        }
-        emit ValidatedAddresses(addressesToValidate);
-        
-        // All addresses are valid. Execute exchange function.
-        EXCHANGE.executeTransaction(
-            salt,
-            signerAddress,
-            signedExchangeTransaction,
-            signature
-        );
-    }
-
-    /// @dev Constructs an array of addresses to be validated.
-    ///      Addresses depend on which Exchange function is to be called
-    ///      (defined by `signedExchangeTransaction` above).
-    /// @param signerAddress Address of transaction signer.
-    /// @return addressesToValidate Array of addresses to validate.
-    function getAddressesToValidate(address signerAddress)
-        internal pure
-        returns (address[] memory addressesToValidate)
-    {
-        bytes4 exchangeFunctionSelector = bytes4(exchangeCalldataload(0));
-        // solhint-disable expression-indent
-        if (
-            exchangeFunctionSelector == BATCH_FILL_ORDERS_SELECTOR              ||
-            exchangeFunctionSelector == BATCH_FILL_ORDERS_NO_THROW_SELECTOR     ||
-            exchangeFunctionSelector == BATCH_FILL_OR_KILL_ORDERS_SELECTOR      ||
-            exchangeFunctionSelector == MARKET_BUY_ORDERS_SELECTOR              ||
-            exchangeFunctionSelector == MARKET_BUY_ORDERS_NO_THROW_SELECTOR     ||
-            exchangeFunctionSelector == MARKET_SELL_ORDERS_SELECTOR             ||
-            exchangeFunctionSelector == MARKET_SELL_ORDERS_NO_THROW_SELECTOR
-        ) {
-            addressesToValidate = loadMakerAddressesFromOrderArray(0);
-            addressesToValidate = addressesToValidate.append(signerAddress);
-        } else if (
-            exchangeFunctionSelector == FILL_ORDER_SELECTOR             ||
-            exchangeFunctionSelector == FILL_ORDER_NO_THROW_SELECTOR    ||
-            exchangeFunctionSelector == FILL_OR_KILL_ORDER_SELECTOR
-        ) {
-            address makerAddress = loadMakerAddressFromOrder(0);
-            addressesToValidate = addressesToValidate.append(makerAddress);
-            addressesToValidate = addressesToValidate.append(signerAddress);
-        } else if (exchangeFunctionSelector == MATCH_ORDERS_SELECTOR) {
-            address leftMakerAddress = loadMakerAddressFromOrder(0);
-            addressesToValidate = addressesToValidate.append(leftMakerAddress);
-            address rightMakerAddress = loadMakerAddressFromOrder(1);
-            addressesToValidate = addressesToValidate.append(rightMakerAddress);
-            addressesToValidate = addressesToValidate.append(signerAddress);
-        } else if (
-            exchangeFunctionSelector != CANCEL_ORDER_SELECTOR           &&
-            exchangeFunctionSelector != BATCH_CANCEL_ORDERS_SELECTOR    &&
-            exchangeFunctionSelector != CANCEL_ORDERS_UP_TO_SELECTOR
-        ) {
-            revert("INVALID_OR_BLOCKED_EXCHANGE_SELECTOR");
-        }
-        // solhint-enable expression-indent
-        return addressesToValidate;
-    }
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/MixinExchangeCalldata.sol
@@ -1,103 +0,0 @@
-    
-    /*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "./mixins/MExchangeCalldata.sol";
-import "@0x/contracts-libs/contracts/libs/LibAddressArray.sol";
-
-
-contract MixinExchangeCalldata is 
-    MExchangeCalldata
-{
-
-    using LibAddressArray for address[];
-
-    /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata,
-    ///      which is accessed through `signedExchangeTransaction`.
-    /// @param offset  Offset into the Exchange calldata.
-    /// @return value  Corresponding 32 byte value stored at `offset`.
-    function exchangeCalldataload(uint256 offset)
-        internal pure
-        returns (bytes32 value)
-    {
-        assembly {
-            // Pointer to exchange transaction
-            // 0x04 for calldata selector
-            // 0x40 to access `signedExchangeTransaction`, which is the third parameter
-            let exchangeTxPtr := calldataload(0x44)
-
-            // Offset into Exchange calldata
-            // We compute this by adding 0x24 to the `exchangeTxPtr` computed above.
-            // 0x04 for calldata selector
-            // 0x20 for length field of `signedExchangeTransaction`
-            let exchangeCalldataOffset := add(exchangeTxPtr, add(0x24, offset))
-            value := calldataload(exchangeCalldataOffset)
-        }
-        return value;
-    }
-
-    /// @dev Convenience function that skips the 4 byte selector when loading
-    ///      from the embedded Exchange calldata.
-    /// @param offset  Offset into the Exchange calldata (minus the 4 byte selector)
-    /// @return value  Corresponding 32 byte value stored at `offset` + 4.
-    function loadExchangeData(uint256 offset)
-        internal pure
-        returns (bytes32 value)
-    {
-        value = exchangeCalldataload(offset + 4);
-        return value;
-    }
-
-    /// @dev Extracts the maker address from an order stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderParamIndex  Index of the order in the Exchange function's signature.
-    /// @return makerAddress The extracted maker address.
-    function loadMakerAddressFromOrder(uint256 orderParamIndex)
-        internal pure
-        returns (address makerAddress)
-    {
-        uint256 orderOffsetInBytes = orderParamIndex * 32;
-        uint256 orderPtr = uint256(loadExchangeData(orderOffsetInBytes));
-        makerAddress = address(loadExchangeData(orderPtr));
-        return makerAddress;
-    }
-
-    /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderArrayParamIndex  Index of the order array in the Exchange function's signature
-    /// @return makerAddresses The extracted maker addresses.
-    function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex)
-        internal pure
-        returns (address[] makerAddresses)
-    {
-        uint256 orderArrayOffsetInBytes = orderArrayParamIndex * 32;
-        uint256 orderArrayPtr = uint256(loadExchangeData(orderArrayOffsetInBytes));
-        uint256 orderArrayLength = uint256(loadExchangeData(orderArrayPtr));
-        uint256 orderArrayLengthInBytes = orderArrayLength * 32;
-        uint256 orderArrayElementPtr = orderArrayPtr + 32;
-        uint256 orderArrayElementEndPtr = orderArrayElementPtr + orderArrayLengthInBytes;
-        for (uint orderPtrOffset = orderArrayElementPtr; orderPtrOffset < orderArrayElementEndPtr; orderPtrOffset += 32) {
-            uint256 orderPtr = uint256(loadExchangeData(orderPtrOffset));
-            address makerAddress = address(loadExchangeData(orderPtr + orderArrayElementPtr));
-            makerAddresses = makerAddresses.append(makerAddress);
-        }
-        return makerAddresses;
-    }
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IBalanceThresholdFilterCore.sol
@@ -1,55 +0,0 @@
-
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IBalanceThresholdFilterCore {
-    
-    /// @dev Executes an Exchange transaction iff the maker and taker meet 
-    ///      the hold at least `BALANCE_THRESHOLD` of the asset `THRESHOLD_ASSET` OR 
-    ///      the exchange function is a cancellation.
-    ///      Supported Exchange functions:
-    ///         - batchFillOrders
-    ///         - batchFillOrdersNoThrow
-    ///         - batchFillOrKillOrders
-    ///         - fillOrder
-    ///         - fillOrderNoThrow
-    ///         - fillOrKillOrder
-    ///         - marketBuyOrders
-    ///         - marketBuyOrdersNoThrow
-    ///         - marketSellOrders
-    ///         - marketSellOrdersNoThrow
-    ///         - matchOrders
-    ///         - cancelOrder
-    ///         - batchCancelOrders
-    ///         - cancelOrdersUpTo
-    ///     Trying to call any other exchange function will throw.
-    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
-    /// @param signerAddress Address of transaction signer.
-    /// @param signedExchangeTransaction AbiV2 encoded calldata.
-    /// @param signature Proof of signer transaction by signer.
-    function executeTransaction(
-        uint256 salt,
-        address signerAddress,
-        bytes signedExchangeTransaction,
-        bytes signature
-    ) 
-        external;
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/interfaces/IThresholdAsset.sol
@@ -1,31 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IThresholdAsset {
-
-    /// @param _owner The address from which the balance will be retrieved
-    /// @return Balance of owner
-    function balanceOf(address _owner)
-        external
-        view
-        returns (uint256);
-
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MBalanceThresholdFilterCore.sol
@@ -1,54 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "../interfaces/IThresholdAsset.sol";
-import "../interfaces/IBalanceThresholdFilterCore.sol";
-
-
-contract MBalanceThresholdFilterCore is
-    IBalanceThresholdFilterCore
-{
-
-    // Points to 0x exchange contract
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-
-    // The asset that must be held by makers/takers
-    IThresholdAsset internal THRESHOLD_ASSET;
-
-    // The minimum balance of `THRESHOLD_ASSET` that must be held by makers/takers
-    uint256 internal BALANCE_THRESHOLD;
-    // solhint-enable var-name-mixedcase
-
-    // Addresses that hold at least `BALANCE_THRESHOLD` of `THRESHOLD_ASSET`
-    event ValidatedAddresses (
-        address[] addresses
-    );
-
-    /// @dev Constructs an array of addresses to be validated.
-    ///      Addresses depend on which Exchange function is to be called
-    ///      (defined by `signedExchangeTransaction` above).
-    /// @param signerAddress Address of transaction signer.
-    /// @return addressesToValidate Array of addresses to validate.
-    function getAddressesToValidate(address signerAddress)
-        internal pure
-        returns (address[] memory addressesToValidate);
-}
--- a/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol
+++ b/contracts/extensions/contracts/BalanceThresholdFilter/mixins/MExchangeCalldata.sol
@@ -1,56 +0,0 @@
-    
-    /*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract MExchangeCalldata {
-
-    /// @dev Emulates the `calldataload` opcode on the embedded Exchange calldata,
-    ///      which is accessed through `signedExchangeTransaction`.
-    /// @param offset  Offset into the Exchange calldata.
-    /// @return value  Corresponding 32 byte value stored at `offset`.
-    function exchangeCalldataload(uint256 offset)
-        internal pure
-        returns (bytes32 value);
-
-    /// @dev Convenience function that skips the 4 byte selector when loading
-    ///      from the embedded Exchange calldata.
-    /// @param offset  Offset into the Exchange calldata (minus the 4 byte selector)
-    /// @return value  Corresponding 32 byte value stored at `offset` + 4.
-    function loadExchangeData(uint256 offset)
-        internal pure
-        returns (bytes32 value);
-
-    /// @dev Extracts the maker address from an order stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderParamIndex  Index of the order in the Exchange function's signature.
-    /// @return makerAddress The extracted maker address.
-    function loadMakerAddressFromOrder(uint256 orderParamIndex)
-        internal pure
-        returns (address makerAddress);
-
-    /// @dev Extracts the maker addresses from an array of orders stored in the Exchange calldata
-    ///      (which is embedded in `signedExchangeTransaction`).
-    /// @param orderArrayParamIndex  Index of the order array in the Exchange function's signature
-    /// @return makerAddresses The extracted maker addresses.
-    function loadMakerAddressesFromOrderArray(uint256 orderArrayParamIndex)
-        internal pure
-        returns (address[] makerAddresses);
-}
--- a/contracts/extensions/contracts/DutchAuction/DutchAuction.sol
+++ b/contracts/extensions/contracts/DutchAuction/DutchAuction.sol
@@ -1,205 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-utils/contracts/utils/SafeMath/SafeMath.sol";
-
-
-contract DutchAuction is
-    SafeMath
-{
-    using LibBytes for bytes;
-
-    // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-
-    struct AuctionDetails {
-        uint256 beginTimeSeconds;    // Auction begin unix timestamp: sellOrder.makerAssetData
-        uint256 endTimeSeconds;      // Auction end unix timestamp: sellOrder.expiryTimeSeconds
-        uint256 beginAmount;         // Auction begin amount: sellOrder.makerAssetData
-        uint256 endAmount;           // Auction end amount: sellOrder.takerAssetAmount
-        uint256 currentAmount;       // Calculated amount given block.timestamp
-        uint256 currentTimeSeconds;  // block.timestamp
-    }
-
-    constructor (address _exchange)
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-    }
-
-    /// @dev Matches the buy and sell orders at an amount given the following: the current block time, the auction
-    ///      start time and the auction begin amount. The sell order is a an order at the lowest amount
-    ///      at the end of the auction. Excess from the match is transferred to the seller.
-    ///      Over time the price moves from beginAmount to endAmount given the current block.timestamp.
-    ///      sellOrder.expiryTimeSeconds is the end time of the auction.
-    ///      sellOrder.takerAssetAmount is the end amount of the auction (lowest possible amount).
-    ///      sellOrder.makerAssetData is the ABI encoded Asset Proxy data with the following data appended
-    ///      buyOrder.makerAssetData is the buyers bid on the auction, must meet the amount for the current block timestamp
-    ///      (uint256 beginTimeSeconds, uint256 beginAmount).
-    ///      This function reverts in the following scenarios:
-    ///         * Auction has not started (auctionDetails.currentTimeSeconds < auctionDetails.beginTimeSeconds)
-    ///         * Auction has expired (auctionDetails.endTimeSeconds < auctionDetails.currentTimeSeconds)
-    ///         * Amount is invalid: Buy order amount is too low (buyOrder.makerAssetAmount < auctionDetails.currentAmount)
-    ///         * Amount is invalid: Invalid begin amount (auctionDetails.beginAmount > auctionDetails.endAmount)
-    ///         * Any failure in the 0x Match Orders
-    /// @param buyOrder The Buyer's order. This order is for the current expected price of the auction.
-    /// @param sellOrder The Seller's order. This order is for the lowest amount (at the end of the auction).
-    /// @param buySignature Proof that order was created by the buyer.
-    /// @param sellSignature Proof that order was created by the seller.
-    /// @return matchedFillResults amounts filled and fees paid by maker and taker of matched orders.
-    function matchOrders(
-        LibOrder.Order memory buyOrder,
-        LibOrder.Order memory sellOrder,
-        bytes memory buySignature,
-        bytes memory sellSignature
-    )
-        public
-        returns (LibFillResults.MatchedFillResults memory matchedFillResults)
-    {
-        AuctionDetails memory auctionDetails = getAuctionDetails(sellOrder);
-        // Ensure the auction has not yet started
-        require(
-            auctionDetails.currentTimeSeconds >= auctionDetails.beginTimeSeconds,
-            "AUCTION_NOT_STARTED"
-        );
-        // Ensure the auction has not expired. This will fail later in 0x but we can save gas by failing early
-        require(
-            sellOrder.expirationTimeSeconds > auctionDetails.currentTimeSeconds,
-            "AUCTION_EXPIRED"
-        );
-        // Validate the buyer amount is greater than the current auction amount
-        require(
-            buyOrder.makerAssetAmount >= auctionDetails.currentAmount,
-            "INVALID_AMOUNT"
-        );
-        // Match orders, maximally filling `buyOrder`
-        matchedFillResults = EXCHANGE.matchOrders(
-            buyOrder,
-            sellOrder,
-            buySignature,
-            sellSignature
-        );
-        // The difference in sellOrder.takerAssetAmount and current amount is given as spread to the matcher
-        // This may include additional spread from the buyOrder.makerAssetAmount and the currentAmount.
-        // e.g currentAmount is 30, sellOrder.takerAssetAmount is 10 and buyOrder.makerAssetamount is 40.
-        // 10 (40-30) is returned to the buyer, 20 (30-10) sent to the seller and 10 has previously
-        // been transferred to the seller during matchOrders
-        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
-        if (leftMakerAssetSpreadAmount > 0) {
-            // ERC20 Asset data itself is encoded as follows:
-            //
-            // | Area     | Offset | Length  | Contents                            |
-            // |----------|--------|---------|-------------------------------------|
-            // | Header   | 0      | 4       | function selector                   |
-            // | Params   |        | 1 * 32  | function parameters:                |
-            // |          | 4      | 12      |   1. token address padding          |
-            // |          | 16     | 20      |   2. token address                  |
-            bytes memory assetData = sellOrder.takerAssetData;
-            address token = assetData.readAddress(16);
-            // Calculate the excess from the buy order. This can occur if the buyer sends in a higher
-            // amount than the calculated current amount
-            uint256 buyerExcessAmount = safeSub(buyOrder.makerAssetAmount, auctionDetails.currentAmount);
-            uint256 sellerExcessAmount = safeSub(leftMakerAssetSpreadAmount, buyerExcessAmount);
-            // Return the difference between auctionDetails.currentAmount and sellOrder.takerAssetAmount
-            // to the seller
-            if (sellerExcessAmount > 0) {
-                IERC20Token(token).transfer(sellOrder.makerAddress, sellerExcessAmount);
-            }
-            // Return the difference between buyOrder.makerAssetAmount and auctionDetails.currentAmount
-            // to the buyer
-            if (buyerExcessAmount > 0) {
-                IERC20Token(token).transfer(buyOrder.makerAddress, buyerExcessAmount);
-            }
-        }
-        return matchedFillResults;
-    }
-
-    /// @dev Calculates the Auction Details for the given order
-    /// @param order The sell order
-    /// @return AuctionDetails
-    function getAuctionDetails(
-        LibOrder.Order memory order
-    )
-        public
-        returns (AuctionDetails memory auctionDetails)
-    {
-        uint256 makerAssetDataLength = order.makerAssetData.length;
-        // It is unknown the encoded data of makerAssetData, we assume the last 64 bytes
-        // are the Auction Details encoding.
-        // Auction Details is encoded as follows:
-        //
-        // | Area     | Offset | Length  | Contents                            |
-        // |----------|--------|---------|-------------------------------------|
-        // | Params   |        | 2 * 32  | parameters:                         |
-        // |          | -64    | 32      |   1. auction begin unix timestamp   |
-        // |          | -32    | 32      |   2. auction begin begin amount     |
-        // ERC20 asset data length is 4+32, 64 for auction details results in min length 100
-        require(
-            makerAssetDataLength >= 100,
-            "INVALID_ASSET_DATA"
-        );
-        uint256 auctionBeginTimeSeconds = order.makerAssetData.readUint256(makerAssetDataLength - 64);
-        uint256 auctionBeginAmount = order.makerAssetData.readUint256(makerAssetDataLength - 32);
-        // Ensure the auction has a valid begin time
-        require(
-            order.expirationTimeSeconds > auctionBeginTimeSeconds,
-            "INVALID_BEGIN_TIME"
-        );
-        uint256 auctionDurationSeconds = order.expirationTimeSeconds-auctionBeginTimeSeconds;
-        // Ensure the auction goes from high to low
-        uint256 minAmount = order.takerAssetAmount;
-        require(
-            auctionBeginAmount > minAmount,
-            "INVALID_AMOUNT"
-        );
-        uint256 amountDelta = auctionBeginAmount-minAmount;
-        // solhint-disable-next-line not-rely-on-time
-        uint256 timestamp = block.timestamp;
-        auctionDetails.beginTimeSeconds = auctionBeginTimeSeconds;
-        auctionDetails.endTimeSeconds = order.expirationTimeSeconds;
-        auctionDetails.beginAmount = auctionBeginAmount;
-        auctionDetails.endAmount = minAmount;
-        auctionDetails.currentTimeSeconds = timestamp;
-
-        uint256 remainingDurationSeconds = order.expirationTimeSeconds-timestamp;
-        if (timestamp < auctionBeginTimeSeconds) {
-            // If the auction has not yet begun the current amount is the auctionBeginAmount
-            auctionDetails.currentAmount = auctionBeginAmount;
-        } else if (timestamp >= order.expirationTimeSeconds) {
-            // If the auction has ended the current amount is the minAmount.
-            // Auction end time is guaranteed by 0x Exchange due to the order expiration
-            auctionDetails.currentAmount = minAmount;
-        } else {
-            auctionDetails.currentAmount = safeAdd(
-                minAmount,
-                safeDiv(
-                    safeMul(remainingDurationSeconds, amountDelta),
-                    auctionDurationSeconds
-                )
-            );
-        }
-        return auctionDetails;
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/Forwarder.sol
+++ b/contracts/extensions/contracts/Forwarder/Forwarder.sol
@@ -1,50 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./MixinWeth.sol";
-import "./MixinForwarderCore.sol";
-import "./libs/LibConstants.sol";
-import "./MixinAssets.sol";
-import "./MixinExchangeWrapper.sol";
-
-
-// solhint-disable no-empty-blocks
-contract Forwarder is
-    LibConstants,
-    MixinWeth,
-    MixinAssets,
-    MixinExchangeWrapper,
-    MixinForwarderCore
-{
-    constructor (
-        address _exchange,
-        bytes memory _zrxAssetData,
-        bytes memory _wethAssetData
-    )
-        public
-        LibConstants(
-            _exchange,
-            _zrxAssetData,
-            _wethAssetData
-        )
-        MixinForwarderCore()
-    {}
-}
--- a/contracts/extensions/contracts/Forwarder/MixinAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinAssets.sol
@@ -1,143 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
-import "./libs/LibConstants.sol";
-import "./mixins/MAssets.sol";
-
-
-contract MixinAssets is
-    Ownable,
-    LibConstants,
-    MAssets
-{
-    using LibBytes for bytes;
-
-    bytes4 constant internal ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)"));
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of ERC20 token to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external
-        onlyOwner
-    {
-        transferAssetToSender(assetData, amount);
-    }
-
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        bytes4 proxyId = assetData.readBytes4(0);
-
-        if (proxyId == ERC20_DATA_ID) {
-            transferERC20Token(assetData, amount);
-        } else if (proxyId == ERC721_DATA_ID) {
-            transferERC721Token(assetData, amount);
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-    }
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        address token = assetData.readAddress(16);
-
-        // Transfer tokens.
-        // We do a raw call so we can check the success separate
-        // from the return data.
-        bool success = token.call(abi.encodeWithSelector(
-            ERC20_TRANSFER_SELECTOR,
-            msg.sender,
-            amount
-        ));
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-        
-        // Check return data.
-        // If there is no return data, we assume the token incorrectly
-        // does not return a bool. In this case we expect it to revert
-        // on failure, which was handled above.
-        // If the token does return data, we require that it is a single
-        // value that evaluates to true.
-        assembly {
-            if returndatasize {
-                success := 0
-                if eq(returndatasize, 32) {
-                    // First 64 bytes of memory are reserved scratch space
-                    returndatacopy(0, 0, 32)
-                    success := mload(0)
-                }
-            }
-        }
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-    }
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        require(
-            amount == 1,
-            "INVALID_AMOUNT"
-        );
-        // Decode asset data.
-        address token = assetData.readAddress(16);
-        uint256 tokenId = assetData.readUint256(36);
-
-        // Perform transfer.
-        IERC721Token(token).transferFrom(
-            address(this),
-            msg.sender,
-            tokenId
-        );
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinExchangeWrapper.sol
@@ -1,260 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./libs/LibConstants.sol";
-import "./mixins/MExchangeWrapper.sol";
-import "@0x/contracts-libs/contracts/libs/LibAbiEncoder.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-import "@0x/contracts-libs/contracts/libs/LibMath.sol";
-
-
-contract MixinExchangeWrapper is
-    LibAbiEncoder,
-    LibFillResults,
-    LibMath,
-    LibConstants,
-    MExchangeWrapper
-{
-    /// @dev Fills the input order.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param signature Proof that order has been created by maker.
-    /// @return Amounts filled and fees paid by maker and taker.
-    function fillOrderNoThrow(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        bytes memory signature
-    )
-        internal
-        returns (FillResults memory fillResults)
-    {
-        // ABI encode calldata for `fillOrder`
-        bytes memory fillOrderCalldata = abiEncodeFillOrder(
-            order,
-            takerAssetFillAmount,
-            signature
-        );
-
-        address exchange = address(EXCHANGE);
-
-        // Call `fillOrder` and handle any exceptions gracefully
-        assembly {
-            let success := call(
-                gas,                                // forward all gas
-                exchange,                           // call address of Exchange contract
-                0,                                  // transfer 0 wei
-                add(fillOrderCalldata, 32),         // pointer to start of input (skip array length in first 32 bytes)
-                mload(fillOrderCalldata),           // length of input
-                fillOrderCalldata,                  // write output over input
-                128                                 // output size is 128 bytes
-            )
-            if success {
-                mstore(fillResults, mload(fillOrderCalldata))
-                mstore(add(fillResults, 32), mload(add(fillOrderCalldata, 32)))
-                mstore(add(fillResults, 64), mload(add(fillOrderCalldata, 64)))
-                mstore(add(fillResults, 96), mload(add(fillOrderCalldata, 96)))
-            }
-        }
-        // fillResults values will be 0 by default if call was unsuccessful
-        return fillResults;
-    }
-
-    /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param orders Array of order specifications.
-    /// @param wethSellAmount Desired amount of WETH to sell.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketSellWeth(
-        LibOrder.Order[] memory orders,
-        uint256 wethSellAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (FillResults memory totalFillResults)
-    {
-        bytes memory makerAssetData = orders[0].makerAssetData;
-        bytes memory wethAssetData = WETH_ASSET_DATA;
-
-        uint256 ordersLength = orders.length;
-        for (uint256 i = 0; i != ordersLength; i++) {
-
-            // We assume that asset being bought by taker is the same for each order.
-            // We assume that asset being sold by taker is WETH for each order.
-            orders[i].makerAssetData = makerAssetData;
-            orders[i].takerAssetData = wethAssetData;
-
-            // Calculate the remaining amount of WETH to sell
-            uint256 remainingTakerAssetFillAmount = safeSub(wethSellAmount, totalFillResults.takerAssetFilledAmount);
-
-            // Attempt to sell the remaining amount of WETH
-            FillResults memory singleFillResults = fillOrderNoThrow(
-                orders[i],
-                remainingTakerAssetFillAmount,
-                signatures[i]
-            );
-
-            // Update amounts filled and fees paid by maker and taker
-            addFillResults(totalFillResults, singleFillResults);
-
-            // Stop execution if the entire amount of takerAsset has been sold
-            if (totalFillResults.takerAssetFilledAmount >= wethSellAmount) {
-                break;
-            }
-        }
-        return totalFillResults;
-    }
-
-    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    ///      The asset being sold by taker must always be WETH.
-    /// @param orders Array of order specifications.
-    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketBuyExactAmountWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (FillResults memory totalFillResults)
-    {
-        bytes memory makerAssetData = orders[0].makerAssetData;
-        bytes memory wethAssetData = WETH_ASSET_DATA;
-
-        uint256 ordersLength = orders.length;
-        for (uint256 i = 0; i != ordersLength; i++) {
-
-            // We assume that asset being bought by taker is the same for each order.
-            // We assume that asset being sold by taker is WETH for each order.
-            orders[i].makerAssetData = makerAssetData;
-            orders[i].takerAssetData = wethAssetData;
-
-            // Calculate the remaining amount of makerAsset to buy
-            uint256 remainingMakerAssetFillAmount = safeSub(makerAssetFillAmount, totalFillResults.makerAssetFilledAmount);
-
-            // Convert the remaining amount of makerAsset to buy into remaining amount
-            // of takerAsset to sell, assuming entire amount can be sold in the current order.
-            // We round up because the exchange rate computed by fillOrder rounds in favor
-            // of the Maker. In this case we want to overestimate the amount of takerAsset.
-            uint256 remainingTakerAssetFillAmount = getPartialAmountCeil(
-                orders[i].takerAssetAmount,
-                orders[i].makerAssetAmount,
-                remainingMakerAssetFillAmount
-            );
-
-            // Attempt to sell the remaining amount of takerAsset
-            FillResults memory singleFillResults = fillOrderNoThrow(
-                orders[i],
-                remainingTakerAssetFillAmount,
-                signatures[i]
-            );
-
-            // Update amounts filled and fees paid by maker and taker
-            addFillResults(totalFillResults, singleFillResults);
-
-            // Stop execution if the entire amount of makerAsset has been bought
-            uint256 makerAssetFilledAmount = totalFillResults.makerAssetFilledAmount;
-            if (makerAssetFilledAmount >= makerAssetFillAmount) {
-                break;
-            }
-        }
-
-        require(
-            makerAssetFilledAmount >= makerAssetFillAmount,
-            "COMPLETE_FILL_FAILED"
-        );
-        return totalFillResults;
-    }
-
-    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee
-    ///      that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues).
-    ///      It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX
-    ///      as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
-    ///      The asset being sold by taker must always be WETH. 
-    /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset.
-    /// @param zrxBuyAmount Desired amount of ZRX to buy.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
-    function marketBuyExactZrxWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 zrxBuyAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (FillResults memory totalFillResults)
-    {
-        // Do nothing if zrxBuyAmount == 0
-        if (zrxBuyAmount == 0) {
-            return totalFillResults;
-        }
-
-        bytes memory zrxAssetData = ZRX_ASSET_DATA;
-        bytes memory wethAssetData = WETH_ASSET_DATA;
-        uint256 zrxPurchased = 0;
-
-        uint256 ordersLength = orders.length;
-        for (uint256 i = 0; i != ordersLength; i++) {
-
-            // All of these are ZRX/WETH, so we can drop the respective assetData from calldata.
-            orders[i].makerAssetData = zrxAssetData;
-            orders[i].takerAssetData = wethAssetData;
-
-            // Calculate the remaining amount of ZRX to buy.
-            uint256 remainingZrxBuyAmount = safeSub(zrxBuyAmount, zrxPurchased);
-
-            // Convert the remaining amount of ZRX to buy into remaining amount
-            // of WETH to sell, assuming entire amount can be sold in the current order.
-            // We round up because the exchange rate computed by fillOrder rounds in favor
-            // of the Maker. In this case we want to overestimate the amount of takerAsset.
-            uint256 remainingWethSellAmount = getPartialAmountCeil(
-                orders[i].takerAssetAmount,
-                safeSub(orders[i].makerAssetAmount, orders[i].takerFee),  // our exchange rate after fees 
-                remainingZrxBuyAmount
-            );
-
-            // Attempt to sell the remaining amount of WETH.
-            FillResults memory singleFillResult = fillOrderNoThrow(
-                orders[i],
-                remainingWethSellAmount,
-                signatures[i]
-            );
-
-            // Update amounts filled and fees paid by maker and taker.
-            addFillResults(totalFillResults, singleFillResult);
-            zrxPurchased = safeSub(totalFillResults.makerAssetFilledAmount, totalFillResults.takerFeePaid);
-
-            // Stop execution if the entire amount of ZRX has been bought.
-            if (zrxPurchased >= zrxBuyAmount) {
-                break;
-            }
-        }
-
-        require(
-            zrxPurchased >= zrxBuyAmount,
-            "COMPLETE_FILL_FAILED"
-        );
-        return totalFillResults;
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinForwarderCore.sol
@@ -1,214 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./libs/LibConstants.sol";
-import "./mixins/MWeth.sol";
-import "./mixins/MAssets.sol";
-import "./mixins/MExchangeWrapper.sol";
-import "./interfaces/IForwarderCore.sol";
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-import "@0x/contracts-libs/contracts/libs/LibMath.sol";
-
-
-contract MixinForwarderCore is
-    LibFillResults,
-    LibMath,
-    LibConstants,
-    MWeth,
-    MAssets,
-    MExchangeWrapper,
-    IForwarderCore
-{
-    using LibBytes for bytes;
-
-    /// @dev Constructor approves ERC20 proxy to transfer ZRX and WETH on this contract's behalf.
-    constructor ()
-        public
-    {
-        address proxyAddress = EXCHANGE.getAssetProxy(ERC20_DATA_ID);
-        require(
-            proxyAddress != address(0),
-            "UNREGISTERED_ASSET_PROXY"
-        );
-        ETHER_TOKEN.approve(proxyAddress, MAX_UINT);
-        ZRX_TOKEN.approve(proxyAddress, MAX_UINT);
-    }
-
-    /// @dev Purchases as much of orders' makerAssets as possible by selling up to 95% of transaction's ETH value.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      5% of ETH value is reserved for paying fees to order feeRecipients (in ZRX) and forwarding contract feeRecipient (in ETH).
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketSellOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            FillResults memory orderFillResults,
-            FillResults memory feeOrderFillResults
-        )
-    {
-        // Convert ETH to WETH.
-        convertEthToWeth();
-
-        uint256 wethSellAmount;
-        uint256 zrxBuyAmount;
-        uint256 makerAssetAmountPurchased;
-        if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
-            // Calculate amount of WETH that won't be spent on ETH fees.
-            wethSellAmount = getPartialAmountFloor(
-                PERCENTAGE_DENOMINATOR,
-                safeAdd(PERCENTAGE_DENOMINATOR, feePercentage),
-                msg.value
-            );
-            // Market sell available WETH.
-            // ZRX fees are paid with this contract's balance.
-            orderFillResults = marketSellWeth(
-                orders,
-                wethSellAmount,
-                signatures
-            );
-            // The fee amount must be deducted from the amount transfered back to sender.
-            makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
-        } else {
-            // 5% of WETH is reserved for filling feeOrders and paying feeRecipient.
-            wethSellAmount = getPartialAmountFloor(
-                MAX_WETH_FILL_PERCENTAGE,
-                PERCENTAGE_DENOMINATOR,
-                msg.value
-            );
-            // Market sell 95% of WETH.
-            // ZRX fees are payed with this contract's balance.
-            orderFillResults = marketSellWeth(
-                orders,
-                wethSellAmount,
-                signatures
-            );
-            // Buy back all ZRX spent on fees.
-            zrxBuyAmount = orderFillResults.takerFeePaid;
-            feeOrderFillResults = marketBuyExactZrxWithWeth(
-                feeOrders,
-                zrxBuyAmount,
-                feeSignatures
-            );
-            makerAssetAmountPurchased = orderFillResults.makerAssetFilledAmount;
-        }
-
-        // Transfer feePercentage of total ETH spent on primary orders to feeRecipient.
-        // Refund remaining ETH to msg.sender.
-        transferEthFeeAndRefund(
-            orderFillResults.takerAssetFilledAmount,
-            feeOrderFillResults.takerAssetFilledAmount,
-            feePercentage,
-            feeRecipient
-        );
-
-        // Transfer purchased assets to msg.sender.
-        transferAssetToSender(orders[0].makerAssetData, makerAssetAmountPurchased);
-    }
-
-    /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketBuyOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            FillResults memory orderFillResults,
-            FillResults memory feeOrderFillResults
-        )
-    {
-        // Convert ETH to WETH.
-        convertEthToWeth();
-
-        uint256 zrxBuyAmount;
-        uint256 makerAssetAmountPurchased;
-        if (orders[0].makerAssetData.equals(ZRX_ASSET_DATA)) {
-            // If the makerAsset is ZRX, it is not necessary to pay fees out of this
-            // contracts's ZRX balance because fees are factored into the price of the order.
-            orderFillResults = marketBuyExactZrxWithWeth(
-                orders,
-                makerAssetFillAmount,
-                signatures
-            );
-            // The fee amount must be deducted from the amount transfered back to sender.
-            makerAssetAmountPurchased = safeSub(orderFillResults.makerAssetFilledAmount, orderFillResults.takerFeePaid);
-        } else {
-            // Attemp to purchase desired amount of makerAsset.
-            // ZRX fees are payed with this contract's balance.
-            orderFillResults = marketBuyExactAmountWithWeth(
-                orders,
-                makerAssetFillAmount,
-                signatures
-            );
-            // Buy back all ZRX spent on fees.
-            zrxBuyAmount = orderFillResults.takerFeePaid;
-            feeOrderFillResults = marketBuyExactZrxWithWeth(
-                feeOrders,
-                zrxBuyAmount,
-                feeSignatures
-            );
-            makerAssetAmountPurchased = orderFillResults.makerAssetFilledAmount;
-        }
-
-        // Transfer feePercentage of total ETH spent on primary orders to feeRecipient.
-        // Refund remaining ETH to msg.sender.
-        transferEthFeeAndRefund(
-            orderFillResults.takerAssetFilledAmount,
-            feeOrderFillResults.takerAssetFilledAmount,
-            feePercentage,
-            feeRecipient
-        );
-
-        // Transfer purchased assets to msg.sender.
-        transferAssetToSender(orders[0].makerAssetData, makerAssetAmountPurchased);
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/MixinWeth.sol
+++ b/contracts/extensions/contracts/Forwarder/MixinWeth.sol
@@ -1,113 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-libs/contracts/libs/LibMath.sol";
-import "./libs/LibConstants.sol";
-import "./mixins/MWeth.sol";
-
-
-contract MixinWeth is
-    LibMath,
-    LibConstants,
-    MWeth
-{
-    /// @dev Default payabale function, this allows us to withdraw WETH
-    function ()
-        public
-        payable
-    {
-        require(
-            msg.sender == address(ETHER_TOKEN),
-            "DEFAULT_FUNCTION_WETH_CONTRACT_ONLY"
-        );
-    }
-
-    /// @dev Converts message call's ETH value into WETH.
-    function convertEthToWeth()
-        internal
-    {
-        require(
-            msg.value > 0,
-            "INVALID_MSG_VALUE"
-        );
-        ETHER_TOKEN.deposit.value(msg.value)();
-    }
-
-    /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
-    ///      Refunds any excess ETH to msg.sender.
-    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
-    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    function transferEthFeeAndRefund(
-        uint256 wethSoldExcludingFeeOrders,
-        uint256 wethSoldForZrx,
-        uint256 feePercentage,
-        address feeRecipient
-    )
-        internal
-    {
-        // Ensure feePercentage is less than 5%.
-        require(
-            feePercentage <= MAX_FEE_PERCENTAGE,
-            "FEE_PERCENTAGE_TOO_LARGE"
-        );
-
-        // Ensure that no extra WETH owned by this contract has been sold.
-        uint256 wethSold = safeAdd(wethSoldExcludingFeeOrders, wethSoldForZrx);
-        require(
-            wethSold <= msg.value,
-            "OVERSOLD_WETH"
-        );
-
-        // Calculate amount of WETH that hasn't been sold.
-        uint256 wethRemaining = safeSub(msg.value, wethSold);
-
-        // Calculate ETH fee to pay to feeRecipient.
-        uint256 ethFee = getPartialAmountFloor(
-            feePercentage,
-            PERCENTAGE_DENOMINATOR,
-            wethSoldExcludingFeeOrders
-        );
-
-        // Ensure fee is less than amount of WETH remaining.
-        require(
-            ethFee <= wethRemaining,
-            "INSUFFICIENT_ETH_REMAINING"
-        );
-    
-        // Do nothing if no WETH remaining
-        if (wethRemaining > 0) {
-            // Convert remaining WETH to ETH
-            ETHER_TOKEN.withdraw(wethRemaining);
-
-            // Pay ETH to feeRecipient
-            if (ethFee > 0) {
-                feeRecipient.transfer(ethFee);
-            }
-
-            // Refund remaining ETH to msg.sender.
-            uint256 ethRefund = safeSub(wethRemaining, ethFee);
-            if (ethRefund > 0) {
-                msg.sender.transfer(ethRefund);
-            }
-        }
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IAssets.sol
@@ -1,34 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IAssets {
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of ERC20 token to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external;
-}
--- a/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarder.sol
@@ -1,30 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./IForwarderCore.sol";
-import "./IAssets.sol";
-
-
-// solhint-disable no-empty-blocks
-contract IForwarder is
-    IForwarderCore,
-    IAssets
-{}
--- a/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
+++ b/contracts/extensions/contracts/Forwarder/interfaces/IForwarderCore.sol
@@ -1,80 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-
-
-contract IForwarderCore {
-
-    /// @dev Purchases as much of orders' makerAssets as possible by selling up to 95% of transaction's ETH value.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      5% of ETH value is reserved for paying fees to order feeRecipients (in ZRX) and forwarding contract feeRecipient (in ETH).
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketSellOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            LibFillResults.FillResults memory orderFillResults,
-            LibFillResults.FillResults memory feeOrderFillResults
-        );
-
-    /// @dev Attempt to purchase makerAssetFillAmount of makerAsset by selling ETH provided with transaction.
-    ///      Any ZRX required to pay fees for primary orders will automatically be purchased by this contract.
-    ///      Any ETH not spent will be refunded to sender.
-    /// @param orders Array of order specifications used containing desired makerAsset and WETH as takerAsset. 
-    /// @param makerAssetFillAmount Desired amount of makerAsset to purchase.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @param feeOrders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset. Used to purchase ZRX for primary order fees.
-    /// @param feeSignatures Proofs that feeOrders have been created by makers.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    /// @return Amounts filled and fees paid by maker and taker for both sets of orders.
-    function marketBuyOrdersWithEth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures,
-        LibOrder.Order[] memory feeOrders,
-        bytes[] memory feeSignatures,
-        uint256  feePercentage,
-        address feeRecipient
-    )
-        public
-        payable
-        returns (
-            LibFillResults.FillResults memory orderFillResults,
-            LibFillResults.FillResults memory feeOrderFillResults
-        );
-}
--- a/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
+++ b/contracts/extensions/contracts/Forwarder/libs/LibConstants.sol
@@ -1,62 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-interfaces/contracts/protocol/Exchange/IExchange.sol";
-import "@0x/contracts-tokens/contracts/tokens/EtherToken/IEtherToken.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-
-
-contract LibConstants {
-
-    using LibBytes for bytes;
-
-    bytes4 constant internal ERC20_DATA_ID = bytes4(keccak256("ERC20Token(address)"));
-    bytes4 constant internal ERC721_DATA_ID = bytes4(keccak256("ERC721Token(address,uint256)"));
-    uint256 constant internal MAX_UINT = 2**256 - 1;
-    uint256 constant internal PERCENTAGE_DENOMINATOR = 10**18; 
-    uint256 constant internal MAX_FEE_PERCENTAGE = 5 * PERCENTAGE_DENOMINATOR / 100;         // 5%
-    uint256 constant internal MAX_WETH_FILL_PERCENTAGE = 95 * PERCENTAGE_DENOMINATOR / 100;  // 95%
- 
-     // solhint-disable var-name-mixedcase
-    IExchange internal EXCHANGE;
-    IEtherToken internal ETHER_TOKEN;
-    IERC20Token internal ZRX_TOKEN;
-    bytes internal ZRX_ASSET_DATA;
-    bytes internal WETH_ASSET_DATA;
-    // solhint-enable var-name-mixedcase
-
-    constructor (
-        address _exchange,
-        bytes memory _zrxAssetData,
-        bytes memory _wethAssetData
-    )
-        public
-    {
-        EXCHANGE = IExchange(_exchange);
-        ZRX_ASSET_DATA = _zrxAssetData;
-        WETH_ASSET_DATA = _wethAssetData;
-
-        address etherToken = _wethAssetData.readAddress(16);
-        address zrxToken = _zrxAssetData.readAddress(16);
-        ETHER_TOKEN = IEtherToken(etherToken);
-        ZRX_TOKEN = IERC20Token(zrxToken);
-    }
-}
--- a/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
+++ b/contracts/extensions/contracts/Forwarder/libs/LibForwarderErrors.sol
@@ -1,34 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-// solhint-disable
-pragma solidity ^0.4.24;
-
-
-/// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
-contract LibForwarderErrors {
-    string constant FEE_PERCENTAGE_TOO_LARGE = "FEE_PROPORTION_TOO_LARGE";                        // Provided fee percentage greater than 5%.
-    string constant INSUFFICIENT_ETH_REMAINING = "INSUFFICIENT_ETH_REMAINING";                    // Not enough ETH remaining to pay feeRecipient.
-    string constant OVERSOLD_WETH = "OVERSOLD_WETH";                                              // More WETH sold than provided with current message call.
-    string constant COMPLETE_FILL_FAILED = "COMPLETE_FILL_FAILED";                                // Desired purchase amount not completely filled (required for ZRX fees only).
-    string constant TRANSFER_FAILED = "TRANSFER_FAILED";                                          // Asset transfer failed.
-    string constant UNSUPPORTED_ASSET_PROXY = "UNSUPPORTED_ASSET_PROXY";                          // Proxy in assetData not supported.
-    string constant DEFAULT_FUNCTION_WETH_CONTRACT_ONLY = "DEFAULT_FUNCTION_WETH_CONTRACT_ONLY";  // Fallback function may only be used for WETH withdrawals.
-    string constant INVALID_MSG_VALUE = "INVALID_MSG_VALUE";                                      // msg.value must be greater than 0.
-    string constant INVALID_AMOUNT = "INVALID_AMOUNT";                                            // Amount must equal 1.
-}
--- a/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MAssets.sol
@@ -1,53 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "../interfaces/IAssets.sol";
-
-
-contract MAssets is
-    IAssets
-{
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal;
-}
--- a/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MExchangeWrapper.sol
@@ -1,87 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-
-
-contract MExchangeWrapper {
-
-    /// @dev Fills the input order.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param order Order struct containing order specifications.
-    /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
-    /// @param signature Proof that order has been created by maker.
-    /// @return Amounts filled and fees paid by maker and taker.
-    function fillOrderNoThrow(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount,
-        bytes memory signature
-    )
-        internal
-        returns (LibFillResults.FillResults memory fillResults);
-
-    /// @dev Synchronously executes multiple calls of fillOrder until total amount of WETH has been sold by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    /// @param orders Array of order specifications.
-    /// @param wethSellAmount Desired amount of WETH to sell.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketSellWeth(
-        LibOrder.Order[] memory orders,
-        uint256 wethSellAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (LibFillResults.FillResults memory totalFillResults);
-
-    /// @dev Synchronously executes multiple fill orders in a single transaction until total amount is bought by taker.
-    ///      Returns false if the transaction would otherwise revert.
-    ///      The asset being sold by taker must always be WETH.
-    /// @param orders Array of order specifications.
-    /// @param makerAssetFillAmount Desired amount of makerAsset to buy.
-    /// @param signatures Proofs that orders have been signed by makers.
-    /// @return Amounts filled and fees paid by makers and taker.
-    function marketBuyExactAmountWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 makerAssetFillAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (LibFillResults.FillResults memory totalFillResults);
-
-    /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account ZRX fees for each order. This will guarantee
-    ///      that at least zrxBuyAmount of ZRX is purchased (sometimes slightly over due to rounding issues).
-    ///      It is possible that a request to buy 200 ZRX will require purchasing 202 ZRX
-    ///      as 2 ZRX is required to purchase the 200 ZRX fee tokens. This guarantees at least 200 ZRX for future purchases.
-    ///      The asset being sold by taker must always be WETH. 
-    /// @param orders Array of order specifications containing ZRX as makerAsset and WETH as takerAsset.
-    /// @param zrxBuyAmount Desired amount of ZRX to buy.
-    /// @param signatures Proofs that orders have been created by makers.
-    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
-    function marketBuyExactZrxWithWeth(
-        LibOrder.Order[] memory orders,
-        uint256 zrxBuyAmount,
-        bytes[] memory signatures
-    )
-        internal
-        returns (LibFillResults.FillResults memory totalFillResults);
-}
--- a/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
+++ b/contracts/extensions/contracts/Forwarder/mixins/MWeth.sol
@@ -1,41 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract MWeth {
-
-    /// @dev Converts message call's ETH value into WETH.
-    function convertEthToWeth()
-        internal;
-
-    /// @dev Transfers feePercentage of WETH spent on primary orders to feeRecipient.
-    ///      Refunds any excess ETH to msg.sender.
-    /// @param wethSoldExcludingFeeOrders Amount of WETH sold when filling primary orders.
-    /// @param wethSoldForZrx Amount of WETH sold when purchasing ZRX required for primary order fees.
-    /// @param feePercentage Percentage of WETH sold that will payed as fee to forwarding contract feeRecipient.
-    /// @param feeRecipient Address that will receive ETH when orders are filled.
-    function transferEthFeeAndRefund(
-        uint256 wethSoldExcludingFeeOrders,
-        uint256 wethSoldForZrx,
-        uint256 feePercentage,
-        address feeRecipient
-    )
-        internal;
-}
--- a/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol
+++ b/contracts/extensions/contracts/OrderMatcher/MixinAssets.sol
@@ -1,195 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contracts-utils/contracts/utils/LibBytes/LibBytes.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC20Token/IERC20Token.sol";
-import "@0x/contracts-tokens/contracts/tokens/ERC721Token/IERC721Token.sol";
-import "./mixins/MAssets.sol";
-import "./libs/LibConstants.sol";
-
-
-contract MixinAssets is
-    MAssets,
-    Ownable,
-    LibConstants
-{
-    using LibBytes for bytes;
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external
-        onlyOwner
-    {
-        transferAssetToSender(assetData, amount);
-    }
-
-    /// @dev Approves or disapproves an AssetProxy to spend asset.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveAssetProxy(
-        bytes assetData,
-        uint256 amount
-    )
-        external
-        onlyOwner
-    {
-        bytes4 proxyId = assetData.readBytes4(0);
-
-        if (proxyId == ERC20_DATA_ID) {
-            approveERC20Token(assetData, amount);
-        } else if (proxyId == ERC721_DATA_ID) {
-            approveERC721Token(assetData, amount);
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-    }
-
-    /// @dev Transfers given amount of asset to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferAssetToSender(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        bytes4 proxyId = assetData.readBytes4(0);
-
-        if (proxyId == ERC20_DATA_ID) {
-            transferERC20Token(assetData, amount);
-        } else if (proxyId == ERC721_DATA_ID) {
-            transferERC721Token(assetData, amount);
-        } else {
-            revert("UNSUPPORTED_ASSET_PROXY");
-        }
-    }
-
-    /// @dev Decodes ERC20 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        // 4 byte id + 12 0 bytes before ABI encoded token address.
-        address token = assetData.readAddress(16);
-
-        // Transfer tokens.
-        // We do a raw call so we can check the success separate
-        // from the return data.
-        bool success = token.call(abi.encodeWithSelector(
-            ERC20_TRANSFER_SELECTOR,
-            msg.sender,
-            amount
-        ));
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-        
-        // Check return data.
-        // If there is no return data, we assume the token incorrectly
-        // does not return a bool. In this case we expect it to revert
-        // on failure, which was handled above.
-        // If the token does return data, we require that it is a single
-        // value that evaluates to true.
-        assembly {
-            if returndatasize {
-                success := 0
-                if eq(returndatasize, 32) {
-                    // First 64 bytes of memory are reserved scratch space
-                    returndatacopy(0, 0, 32)
-                    success := mload(0)
-                }
-            }
-        }
-        require(
-            success,
-            "TRANSFER_FAILED"
-        );
-    }
-
-    /// @dev Decodes ERC721 assetData and transfers given amount to sender.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to transfer to sender.
-    function transferERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        require(
-            amount == 1,
-            "INVALID_AMOUNT"
-        );
-        // Decode asset data.
-        // 4 byte id + 12 0 bytes before ABI encoded token address.
-        address token = assetData.readAddress(16);
-        // 4 byte id + 32 byte ABI encoded token address before token id.
-        uint256 tokenId = assetData.readUint256(36);
-
-        // Perform transfer.
-        IERC721Token(token).transferFrom(
-            address(this),
-            msg.sender,
-            tokenId
-        );
-    }
-
-    /// @dev Sets approval for ERC20 AssetProxy.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveERC20Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        address token = assetData.readAddress(16);
-        require(
-            IERC20Token(token).approve(ERC20_PROXY_ADDRESS, amount),
-            "APPROVAL_FAILED"
-        );
-    }
-
-    /// @dev Sets approval for ERC721 AssetProxy.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveERC721Token(
-        bytes memory assetData,
-        uint256 amount
-    )
-        internal
-    {
-        address token = assetData.readAddress(16);
-        bool approval = amount >= 1;
-        IERC721Token(token).setApprovalForAll(ERC721_PROXY_ADDRESS, approval);
-    }
-}
--- a/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol
+++ b/contracts/extensions/contracts/OrderMatcher/MixinMatchOrders.sol
@@ -1,86 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "./libs/LibConstants.sol";
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-import "@0x/contracts-libs/contracts/libs/LibFillResults.sol";
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-
-
-contract MixinMatchOrders is
-    Ownable,
-    LibConstants
-{
-    /// @dev Match two complementary orders that have a profitable spread.
-    ///      Each order is filled at their respective price point. However, the calculations are
-    ///      carried out as though the orders are both being filled at the right order's price point.
-    ///      The profit made by the left order is then used to fill the right order as much as possible.
-    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
-    /// @param leftOrder First order to match.
-    /// @param rightOrder Second order to match.
-    /// @param leftSignature Proof that order was created by the left maker.
-    /// @param rightSignature Proof that order was created by the right maker.
-    function matchOrders(
-        LibOrder.Order memory leftOrder,
-        LibOrder.Order memory rightOrder,
-        bytes memory leftSignature,
-        bytes memory rightSignature
-    )
-        public
-        onlyOwner
-    {
-        // Match orders, maximally filling `leftOrder`
-        LibFillResults.MatchedFillResults memory matchedFillResults = EXCHANGE.matchOrders(
-            leftOrder,
-            rightOrder,
-            leftSignature,
-            rightSignature
-        );
-
-        uint256 leftMakerAssetSpreadAmount = matchedFillResults.leftMakerAssetSpreadAmount;
-        uint256 rightOrderTakerAssetAmount = rightOrder.takerAssetAmount;
-
-        // Do not attempt to call `fillOrder` if no spread was taken or `rightOrder` has been completely filled
-        if (leftMakerAssetSpreadAmount == 0 || matchedFillResults.right.takerAssetFilledAmount == rightOrderTakerAssetAmount) {
-            return;
-        }
-
-        // The `assetData` fields of the `rightOrder` could have been null for the `matchOrders` call. We reassign them before calling `fillOrder`.
-        rightOrder.makerAssetData = leftOrder.takerAssetData;
-        rightOrder.takerAssetData = leftOrder.makerAssetData;
-
-        // Query `rightOrder` info to check if it has been completely filled
-        // We need to make this check in case the `rightOrder` was partially filled before the `matchOrders` call
-        LibOrder.OrderInfo memory orderInfo = EXCHANGE.getOrderInfo(rightOrder);
-
-        // Do not attempt to call `fillOrder` if order has been completely filled
-        if (orderInfo.orderTakerAssetFilledAmount == rightOrderTakerAssetAmount) {
-            return;
-        }
-
-        // We do not need to pass in a signature since it was already validated in the `matchOrders` call
-        EXCHANGE.fillOrder(
-            rightOrder,
-            leftMakerAssetSpreadAmount,
-            ""
-        );
-    }
-}
--- a/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol
+++ b/contracts/extensions/contracts/OrderMatcher/OrderMatcher.sol
@@ -1,38 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity 0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-utils/contracts/utils/Ownable/Ownable.sol";
-import "./libs/LibConstants.sol";
-import "./MixinMatchOrders.sol";
-import "./MixinAssets.sol";
-
-
-// solhint-disable no-empty-blocks
-contract OrderMatcher is
-    MixinMatchOrders,
-    MixinAssets
-{
-    constructor (address _exchange)
-        public
-        LibConstants(_exchange)
-        Ownable()
-    {}
-}
--- a/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IAssets.sol
@@ -1,43 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-
-contract IAssets {
-
-    /// @dev Withdraws assets from this contract. The contract requires a ZRX balance in order to 
-    ///      function optimally, and this function allows the ZRX to be withdrawn by owner. It may also be
-    ///      used to withdraw assets that were accidentally sent to this contract.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to withdraw.
-    function withdrawAsset(
-        bytes assetData,
-        uint256 amount
-    )
-        external;
-
-    /// @dev Approves or disapproves an AssetProxy to spend asset.
-    /// @param assetData Byte array encoded for the respective asset proxy.
-    /// @param amount Amount of asset to approve for respective proxy.
-    function approveAssetProxy(
-        bytes assetData,
-        uint256 amount
-    )
-        external;
-}
--- a/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IMatchOrders.sol
@@ -1,43 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-libs/contracts/libs/LibOrder.sol";
-
-
-contract IMatchOrders {
-
-    /// @dev Match two complementary orders that have a profitable spread.
-    ///      Each order is filled at their respective price point. However, the calculations are
-    ///      carried out as though the orders are both being filled at the right order's price point.
-    ///      The profit made by the left order is then used to fill the right order as much as possible.
-    ///      This results in a spread being taken in terms of both assets. The spread is held within this contract.
-    /// @param leftOrder First order to match.
-    /// @param rightOrder Second order to match.
-    /// @param leftSignature Proof that order was created by the left maker.
-    /// @param rightSignature Proof that order was created by the right maker.
-    function matchOrders(
-        LibOrder.Order memory leftOrder,
-        LibOrder.Order memory rightOrder,
-        bytes memory leftSignature,
-        bytes memory rightSignature
-    )
-        public;
-}
--- a/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol
+++ b/contracts/extensions/contracts/OrderMatcher/interfaces/IOrderMatcher.sol
@@ -1,31 +0,0 @@
-/*
-
-  Copyright 2018 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.4.24;
-
-import "@0x/contract-utils/contracts/utils/Ownable/IOwnable.sol";
-import "./IMatchOrders.sol";
-import "./IAssets.sol";
-
-
-// solhint-disable no-empty-blocks
-contract IOrderMatcher is
-    IOwnable,
-    IMatchOrders,
-    IAssets
-{}
--- a/Show More
+++ b/Show More