diff --git a/src/main/java/org/qortal/data/transaction/TransactionData.java b/src/main/java/org/qortal/data/transaction/TransactionData.java
index 060901f2..ec1139f4 100644
--- a/src/main/java/org/qortal/data/transaction/TransactionData.java
+++ b/src/main/java/org/qortal/data/transaction/TransactionData.java
@@ -128,6 +128,10 @@ public abstract class TransactionData {
 		return this.txGroupId;
 	}
 
+	public void setTxGroupId(int txGroupId) {
+		this.txGroupId = txGroupId;
+	}
+
 	public byte[] getReference() {
 		return this.reference;
 	}
diff --git a/src/main/java/org/qortal/group/Group.java b/src/main/java/org/qortal/group/Group.java
index 1dbb18b0..465743a9 100644
--- a/src/main/java/org/qortal/group/Group.java
+++ b/src/main/java/org/qortal/group/Group.java
@@ -80,6 +80,9 @@ public class Group {
 	// Useful constants
 	public static final int NO_GROUP = 0;
 
+	// Null owner address corresponds with public key "11111111111111111111111111111111"
+	public static String NULL_OWNER_ADDRESS = "QdSnUy6sUiEnaN87dWmE92g1uQjrvPgrWG";
+
 	public static final int MIN_NAME_SIZE = 3;
 	public static final int MAX_NAME_SIZE = 32;
 	public static final int MAX_DESCRIPTION_SIZE = 128;
diff --git a/src/main/java/org/qortal/transaction/AddGroupAdminTransaction.java b/src/main/java/org/qortal/transaction/AddGroupAdminTransaction.java
index 15dc51bf..f38638c5 100644
--- a/src/main/java/org/qortal/transaction/AddGroupAdminTransaction.java
+++ b/src/main/java/org/qortal/transaction/AddGroupAdminTransaction.java
@@ -2,6 +2,7 @@ package org.qortal.transaction;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
@@ -64,15 +65,24 @@ public class AddGroupAdminTransaction extends Transaction {
 
 		Account owner = getOwner();
 		String groupOwner = this.repository.getGroupRepository().getOwner(groupId);
+		boolean groupOwnedByNullAccount = Objects.equals(groupOwner, Group.NULL_OWNER_ADDRESS);
 
-		// Check transaction's public key matches group's current owner
-		if (!owner.getAddress().equals(groupOwner))
+		// Require approval if transaction relates to a group owned by the null account
+		if (groupOwnedByNullAccount && !this.needsGroupApproval())
+			return ValidationResult.GROUP_APPROVAL_REQUIRED;
+
+		// Check transaction's public key matches group's current owner (except for groups owned by the null account)
+		if (!groupOwnedByNullAccount && !owner.getAddress().equals(groupOwner))
 			return ValidationResult.INVALID_GROUP_OWNER;
 
 		// Check address is a group member
 		if (!this.repository.getGroupRepository().memberExists(groupId, memberAddress))
 			return ValidationResult.NOT_GROUP_MEMBER;
 
+		// Check transaction creator is a group member
+		if (!this.repository.getGroupRepository().memberExists(groupId, this.getCreator().getAddress()))
+			return ValidationResult.NOT_GROUP_MEMBER;
+
 		// Check group member is not already an admin
 		if (this.repository.getGroupRepository().adminExists(groupId, memberAddress))
 			return ValidationResult.ALREADY_GROUP_ADMIN;
diff --git a/src/main/java/org/qortal/transaction/RemoveGroupAdminTransaction.java b/src/main/java/org/qortal/transaction/RemoveGroupAdminTransaction.java
index 3e5f1e6d..043b5423 100644
--- a/src/main/java/org/qortal/transaction/RemoveGroupAdminTransaction.java
+++ b/src/main/java/org/qortal/transaction/RemoveGroupAdminTransaction.java
@@ -2,6 +2,7 @@ package org.qortal.transaction;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Objects;
 
 import org.qortal.account.Account;
 import org.qortal.asset.Asset;
@@ -65,11 +66,21 @@ public class RemoveGroupAdminTransaction extends Transaction {
 			return ValidationResult.GROUP_DOES_NOT_EXIST;
 
 		Account owner = getOwner();
+		String groupOwner = this.repository.getGroupRepository().getOwner(groupId);
+		boolean groupOwnedByNullAccount = Objects.equals(groupOwner, Group.NULL_OWNER_ADDRESS);
 
-		// Check transaction's public key matches group's current owner
-		if (!owner.getAddress().equals(groupData.getOwner()))
+		// Require approval if transaction relates to a group owned by the null account
+		if (groupOwnedByNullAccount && !this.needsGroupApproval())
+			return ValidationResult.GROUP_APPROVAL_REQUIRED;
+
+		// Check transaction's public key matches group's current owner (except for groups owned by the null account)
+		if (!groupOwnedByNullAccount && !owner.getAddress().equals(groupOwner))
 			return ValidationResult.INVALID_GROUP_OWNER;
 
+		// Check transaction creator is a group member
+		if (!this.repository.getGroupRepository().memberExists(groupId, this.getCreator().getAddress()))
+			return ValidationResult.NOT_GROUP_MEMBER;
+
 		Account admin = getAdmin();
 
 		// Check member is an admin
diff --git a/src/main/java/org/qortal/transaction/Transaction.java b/src/main/java/org/qortal/transaction/Transaction.java
index b56d48cf..203cc342 100644
--- a/src/main/java/org/qortal/transaction/Transaction.java
+++ b/src/main/java/org/qortal/transaction/Transaction.java
@@ -1,13 +1,7 @@
 package org.qortal.transaction;
 
 import java.math.BigInteger;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Comparator;
-import java.util.EnumSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Map;
+import java.util.*;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.function.Predicate;
 
@@ -69,8 +63,8 @@ public abstract class Transaction {
 		AT(21, false),
 		CREATE_GROUP(22, true),
 		UPDATE_GROUP(23, true),
-		ADD_GROUP_ADMIN(24, false),
-		REMOVE_GROUP_ADMIN(25, false),
+		ADD_GROUP_ADMIN(24, true),
+		REMOVE_GROUP_ADMIN(25, true),
 		GROUP_BAN(26, false),
 		CANCEL_GROUP_BAN(27, false),
 		GROUP_KICK(28, false),
@@ -250,6 +244,7 @@ public abstract class Transaction {
 		INVALID_TIMESTAMP_SIGNATURE(95),
 		ADDRESS_BLOCKED(96),
 		NAME_BLOCKED(97),
+		GROUP_APPROVAL_REQUIRED(98),
 		INVALID_BUT_OK(999),
 		NOT_YET_RELEASED(1000);
 
@@ -760,9 +755,13 @@ public abstract class Transaction {
 			// Group no longer exists? Possibly due to blockchain orphaning undoing group creation?
 			return true; // stops tx being included in block but it will eventually expire
 
+		String groupOwner = this.repository.getGroupRepository().getOwner(txGroupId);
+		boolean groupOwnedByNullAccount = Objects.equals(groupOwner, Group.NULL_OWNER_ADDRESS);
+
 		// If transaction's creator is group admin (of group with ID txGroupId) then auto-approve
+		// This is disabled for null-owned groups, since these require approval from other admins
 		PublicKeyAccount creator = this.getCreator();
-		if (groupRepository.adminExists(txGroupId, creator.getAddress()))
+		if (!groupOwnedByNullAccount && groupRepository.adminExists(txGroupId, creator.getAddress()))
 			return false;
 
 		return true;
diff --git a/src/test/java/org/qortal/test/group/DevGroupAdminTests.java b/src/test/java/org/qortal/test/group/DevGroupAdminTests.java
new file mode 100644
index 00000000..131359c6
--- /dev/null
+++ b/src/test/java/org/qortal/test/group/DevGroupAdminTests.java
@@ -0,0 +1,388 @@
+package org.qortal.test.group;
+
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.qortal.account.PrivateKeyAccount;
+import org.qortal.data.transaction.*;
+import org.qortal.group.Group;
+import org.qortal.group.Group.ApprovalThreshold;
+import org.qortal.repository.DataException;
+import org.qortal.repository.Repository;
+import org.qortal.repository.RepositoryManager;
+import org.qortal.test.common.BlockUtils;
+import org.qortal.test.common.Common;
+import org.qortal.test.common.GroupUtils;
+import org.qortal.test.common.TransactionUtils;
+import org.qortal.test.common.transaction.TestTransaction;
+import org.qortal.transaction.Transaction;
+import org.qortal.transaction.Transaction.ValidationResult;
+import org.qortal.utils.Base58;
+
+import static org.junit.Assert.*;
+
+/**
+ * Dev group admin tests
+ *
+ * The dev group (ID 1) is owned by the null account with public key 11111111111111111111111111111111
+ * To regain access to otherwise blocked owner-based rules, it has different validation logic
+ * which applies to groups with this same null owner.
+ *
+ * The main difference is that approval is required for certain transaction types relating to
+ * null-owned groups. This allows existing admins to approve updates to the group (using group's
+ * approval threshold) instead of these actions being performed by the owner.
+ *
+ * Since these apply to all null-owned groups, this allows anyone to update their group to
+ * the null owner if they want to take advantage of this decentralized approval system.
+ *
+ * Currently, the affected transaction types are:
+ * - AddGroupAdminTransaction
+ * - RemoveGroupAdminTransaction
+ *
+ * This same approach could ultimately be applied to other group transactions too.
+ */
+public class DevGroupAdminTests extends Common {
+
+	private static final int DEV_GROUP_ID = 1;
+
+	@Before
+	public void beforeTest() throws DataException {
+		Common.useDefaultSettings();
+	}
+
+	@After
+	public void afterTest() throws DataException {
+		Common.orphanCheck();
+	}
+
+	@Test
+	public void testGroupKickMember() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to kick Bob
+			ValidationResult result = groupKick(repository, alice, groupId, bob.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			joinGroup(repository, bob, groupId);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to kick Bob
+			result = groupKick(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Confirm Bob no longer a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Orphan last block
+			BlockUtils.orphanLastBlock(repository);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+		}
+	}
+
+	@Test
+	public void testGroupKickAdmin() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			joinGroup(repository, bob, groupId);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Promote Bob to admin
+			TransactionData addGroupAdminTransactionData = addGroupAdmin(repository, alice, groupId, bob.getAddress());
+
+			// Confirm transaction needs approval, and hasn't been approved
+			Transaction.ApprovalStatus approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.PENDING, approvalStatus);
+
+			// Have Alice approve Bob's approval-needed transaction
+			GroupUtils.approveTransaction(repository, "alice", addGroupAdminTransactionData.getSignature(), true);
+
+			// Mint a block so that the transaction becomes approved
+			BlockUtils.mintBlock(repository);
+
+			// Confirm transaction is approved
+			approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.APPROVED, approvalStatus);
+
+			// Confirm Bob is now admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Attempt to kick Bob
+			ValidationResult result = groupKick(repository, alice, groupId, bob.getAddress());
+			// Shouldn't be allowed
+			assertEquals(ValidationResult.INVALID_GROUP_OWNER, result);
+
+			// Confirm Bob is still a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Confirm Bob still an admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Orphan last block
+			BlockUtils.orphanLastBlock(repository);
+
+			// Confirm Bob no longer an admin (ADD_GROUP_ADMIN no longer approved)
+			assertFalse(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Have Alice try to kick herself!
+			result = groupKick(repository, alice, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Have Bob try to kick Alice
+			result = groupKick(repository, bob, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+		}
+	}
+
+	@Test
+	public void testGroupBanMember() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to cancel non-existent Bob ban
+			ValidationResult result = cancelGroupBan(repository, alice, groupId, bob.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Attempt to ban Bob
+			result = groupBan(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Orphan last block (Bob ban)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed group-ban transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			result = joinGroup(repository, bob, groupId);
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// Attempt to ban Bob
+			result = groupBan(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Confirm Bob no longer a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Cancel Bob's ban
+			result = cancelGroupBan(repository, alice, groupId, bob.getAddress());
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Orphan last block (Bob join)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed join-group transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Orphan last block (Cancel Bob ban)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed cancel-ban transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Bob attempts to rejoin
+			result = joinGroup(repository, bob, groupId);
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Orphan last block (Bob ban)
+			BlockUtils.orphanLastBlock(repository);
+			// Delete unconfirmed group-ban transaction
+			TransactionUtils.deleteUnconfirmedTransactions(repository);
+
+			// Confirm Bob now a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+		}
+	}
+
+	@Test
+	public void testGroupBanAdmin() throws DataException {
+		try (final Repository repository = RepositoryManager.getRepository()) {
+			PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+			PrivateKeyAccount bob = Common.getTestAccount(repository, "bob");
+
+			// Dev group
+			int groupId = DEV_GROUP_ID;
+
+			// Confirm Bob is not a member
+			assertFalse(isMember(repository, bob.getAddress(), groupId));
+
+			// Alice to invite Bob, as it's a closed group
+			groupInvite(repository, alice, groupId, bob.getAddress(), 3600);
+
+			// Bob to join
+			ValidationResult result = joinGroup(repository, bob, groupId);
+			// Should be OK
+			assertEquals(ValidationResult.OK, result);
+
+			// Promote Bob to admin
+			TransactionData addGroupAdminTransactionData = addGroupAdmin(repository, alice, groupId, bob.getAddress());
+
+			// Confirm transaction needs approval, and hasn't been approved
+			Transaction.ApprovalStatus approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.PENDING, approvalStatus);
+
+			// Have Alice approve Bob's approval-needed transaction
+			GroupUtils.approveTransaction(repository, "alice", addGroupAdminTransactionData.getSignature(), true);
+
+			// Mint a block so that the transaction becomes approved
+			BlockUtils.mintBlock(repository);
+
+			// Confirm transaction is approved
+			approvalStatus = GroupUtils.getApprovalStatus(repository, addGroupAdminTransactionData.getSignature());
+			assertEquals("incorrect transaction approval status", Transaction.ApprovalStatus.APPROVED, approvalStatus);
+
+			// Confirm Bob is now admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Attempt to ban Bob
+			result = groupBan(repository, alice, groupId, bob.getAddress());
+			// .. but we can't, because Bob is an admin and the group has no owner
+			assertEquals(ValidationResult.INVALID_GROUP_OWNER, result);
+
+			// Confirm Bob still a member
+			assertTrue(isMember(repository, bob.getAddress(), groupId));
+
+			// ... and still an admin
+			assertTrue(isAdmin(repository, bob.getAddress(), groupId));
+
+			// Have Alice try to ban herself!
+			result = groupBan(repository, alice, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+
+			// Have Bob try to ban Alice
+			result = groupBan(repository, bob, groupId, alice.getAddress());
+			// Should NOT be OK
+			assertNotSame(ValidationResult.OK, result);
+		}
+	}
+
+
+	private ValidationResult joinGroup(Repository repository, PrivateKeyAccount joiner, int groupId) throws DataException {
+		JoinGroupTransactionData transactionData = new JoinGroupTransactionData(TestTransaction.generateBase(joiner), groupId);
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, joiner);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private void groupInvite(Repository repository, PrivateKeyAccount admin, int groupId, String invitee, int timeToLive) throws DataException {
+		GroupInviteTransactionData transactionData = new GroupInviteTransactionData(TestTransaction.generateBase(admin), groupId, invitee, timeToLive);
+		TransactionUtils.signAndMint(repository, transactionData, admin);
+	}
+
+	private ValidationResult groupKick(Repository repository, PrivateKeyAccount admin, int groupId, String member) throws DataException {
+		GroupKickTransactionData transactionData = new GroupKickTransactionData(TestTransaction.generateBase(admin), groupId, member, "testing");
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, admin);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private ValidationResult groupBan(Repository repository, PrivateKeyAccount admin, int groupId, String member) throws DataException {
+		GroupBanTransactionData transactionData = new GroupBanTransactionData(TestTransaction.generateBase(admin), groupId, member, "testing", 0);
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, admin);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private ValidationResult cancelGroupBan(Repository repository, PrivateKeyAccount admin, int groupId, String member) throws DataException {
+		CancelGroupBanTransactionData transactionData = new CancelGroupBanTransactionData(TestTransaction.generateBase(admin), groupId, member);
+		ValidationResult result = TransactionUtils.signAndImport(repository, transactionData, admin);
+
+		if (result == ValidationResult.OK)
+			BlockUtils.mintBlock(repository);
+
+		return result;
+	}
+
+	private TransactionData addGroupAdmin(Repository repository, PrivateKeyAccount owner, int groupId, String member) throws DataException {
+		AddGroupAdminTransactionData transactionData = new AddGroupAdminTransactionData(TestTransaction.generateBase(owner), groupId, member);
+		transactionData.setTxGroupId(groupId);
+		TransactionUtils.signAndMint(repository, transactionData, owner);
+		return transactionData;
+	}
+
+	private boolean isMember(Repository repository, String address, int groupId) throws DataException {
+		return repository.getGroupRepository().memberExists(groupId, address);
+	}
+
+	private boolean isAdmin(Repository repository, String address, int groupId) throws DataException {
+		return repository.getGroupRepository().adminExists(groupId, address);
+	}
+
+}
diff --git a/src/test/resources/test-chain-v2.json b/src/test/resources/test-chain-v2.json
index c0fb9861..84c692d5 100644
--- a/src/test/resources/test-chain-v2.json
+++ b/src/test/resources/test-chain-v2.json
@@ -91,6 +91,8 @@
 
 			{ "type": "CREATE_GROUP", "creatorPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "groupName": "dev-group", "description": "developer group", "isOpen": false, "approvalThreshold": "PCT100", "minimumBlockDelay": 0, "maximumBlockDelay": 1440 },
 
+			{ "type": "UPDATE_GROUP", "ownerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "groupId": 1, "newOwner": "QdSnUy6sUiEnaN87dWmE92g1uQjrvPgrWG", "newDescription": "developer group", "newIsOpen": false, "newApprovalThreshold": "PCT40", "minimumBlockDelay": 10, "maximumBlockDelay": 1440 },
+
 			{ "type": "ISSUE_ASSET", "issuerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "assetName": "TEST", "description": "test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
 			{ "type": "ISSUE_ASSET", "issuerPublicKey": "C6wuddsBV3HzRrXUtezE7P5MoRXp5m3mEDokRDGZB6ry", "assetName": "OTHER", "description": "other test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
 			{ "type": "ISSUE_ASSET", "issuerPublicKey": "2tiMr5LTpaWCgbRvkPK8TFd7k63DyHJMMFFsz9uBf1ZP", "assetName": "GOLD", "description": "gold test asset", "data": "", "quantity": "1000000", "isDivisible": true, "fee": 0 },
diff --git a/tools/approve-dev-transaction.sh b/tools/approve-dev-transaction.sh
new file mode 100755
index 00000000..6b611b59
--- /dev/null
+++ b/tools/approve-dev-transaction.sh
@@ -0,0 +1,97 @@
+#!/usr/bin/env bash
+
+port=12391
+if [ $# -gt 0 -a "$1" = "-t" ]; then
+	port=62391
+fi
+
+printf "Searching for auto-update transactions to approve...\n";
+
+tx=$( curl --silent --url "http://localhost:${port}/transactions/search?txGroupId=1&txType=ADD_GROUP_ADMIN&txType=REMOVE_GROUP_ADMIN&confirmationStatus=CONFIRMED&limit=1&reverse=true" );
+if fgrep --silent '"approvalStatus":"PENDING"' <<< "${tx}"; then
+	true
+else
+	echo "Can't find any pending transactions"
+	exit
+fi
+
+sig=$( perl -n -e 'print $1 if m/"signature":"(\w+)"/' <<< "${tx}" )
+if [ -z "${sig}" ]; then
+	printf "Can't find transaction signature in JSON:\n%s\n" "${tx}"
+	exit
+fi
+
+printf "Found transaction %s\n" $sig;
+
+printf "\nPaste your dev account private key:\n";
+IFS=
+read -s privkey
+printf "\n"
+
+# Convert to public key
+pubkey=$( curl --silent --url "http://localhost:${port}/utils/publickey" --data @- <<< "${privkey}" );
+if egrep -v --silent '^\w{44,46}$' <<< "${pubkey}"; then
+	printf "Invalid response from API - was your private key correct?\n%s\n" "${pubkey}"
+	exit
+fi
+printf "Your public key: %s\n" ${pubkey}
+
+# Convert to address
+address=$( curl --silent --url "http://localhost:${port}/addresses/convert/${pubkey}" );
+printf "Your address: %s\n" ${address}
+
+# Grab last reference
+lastref=$( curl --silent --url "http://localhost:${port}/addresses/lastreference/{$address}" );
+printf "Your last reference: %s\n" ${lastref}
+
+# Build GROUP_APPROVAL transaction
+timestamp=$( date +%s )000
+tx_json=$( cat <<TX_END
+{
+  "timestamp": ${timestamp},
+  "reference": "${lastref}",
+  "fee": 0.001,
+  "txGroupId": 0,
+  "adminPublicKey": "${pubkey}",
+  "pendingSignature": "${sig}",
+  "approval": true
+}
+TX_END
+)
+
+raw_tx=$( curl --silent --header "Content-Type: application/json" --url "http://localhost:${port}/groups/approval" --data @- <<< "${tx_json}" )
+if egrep -v --silent '^\w{100,}' <<< "${raw_tx}"; then
+	printf "Building GROUP_APPROVAL transaction failed:\n%s\n" "${raw_tx}"
+	exit
+fi
+printf "\nRaw approval tx:\n%s\n" ${raw_tx}
+
+# sign
+sign_json=$( cat <<SIGN_END
+{
+  "privateKey": "${privkey}",
+  "transactionBytes": "${raw_tx}"
+}
+SIGN_END
+)
+signed_tx=$( curl --silent --header "Content-Type: application/json" --url "http://localhost:${port}/transactions/sign" --data @- <<< "${sign_json}" )
+printf "\nSigned tx:\n%s\n" ${signed_tx}
+if egrep -v --silent '^\w{100,}' <<< "${signed_tx}"; then
+	printf "Signing GROUP_APPROVAL transaction failed:\n%s\n" "${signed_tx}"
+	exit
+fi
+
+# ready to publish?
+plural="s"
+printf "\n"
+for ((seconds = 5; seconds > 0; seconds--)); do
+	if [ "${seconds}" = "1" ]; then
+		plural=""
+	fi
+	printf "\rBroadcasting in %d second%s...(CTRL-C) to abort " $seconds $plural
+	sleep 1
+done
+
+printf "\rBroadcasting signed GROUP_APPROVAL transaction...      \n"
+result=$( curl --silent --url "http://localhost:${port}/transactions/process" --data @- <<< "${signed_tx}" )
+printf "API response:\n%s\n" "${result}"
diff --git a/tools/tx.pl b/tools/tx.pl
index db6958e2..fe3cd872 100755
--- a/tools/tx.pl
+++ b/tools/tx.pl
@@ -71,9 +71,14 @@ our %TRANSACTION_TYPES = (
 	},
 	add_group_admin => {
 		url => 'groups/addadmin',
-		required => [qw(groupId member)],
+		required => [qw(groupId txGroupId member)],
 		key_name => 'ownerPublicKey',
 	},
+	remove_group_admin => {
+        url => 'groups/removeadmin',
+        required => [qw(groupId txGroupId admin)],
+        key_name => 'ownerPublicKey',
+    },
 	group_approval => {
 		url => 'groups/approval',
 		required => [qw(pendingSignature approval)],