diff --git a/src/main/java/org/qortal/transaction/ArbitraryTransaction.java b/src/main/java/org/qortal/transaction/ArbitraryTransaction.java
index 4d20f3cd..9a11a820 100644
--- a/src/main/java/org/qortal/transaction/ArbitraryTransaction.java
+++ b/src/main/java/org/qortal/transaction/ArbitraryTransaction.java
@@ -90,7 +90,8 @@ public class ArbitraryTransaction extends Transaction {
 
 		// Disable reference checking after feature trigger timestamp
 		if (this.arbitraryTransactionData.getTimestamp() >= BlockChain.getInstance().getDisableReferenceTimestamp()) {
-			return true;
+			// Allow any non-null value
+			return this.arbitraryTransactionData.getReference() != null;
 		}
 
 		if (this.arbitraryTransactionData.getReference() == null) {
diff --git a/src/main/java/org/qortal/transaction/AtTransaction.java b/src/main/java/org/qortal/transaction/AtTransaction.java
index d278a909..be0388a1 100644
--- a/src/main/java/org/qortal/transaction/AtTransaction.java
+++ b/src/main/java/org/qortal/transaction/AtTransaction.java
@@ -78,7 +78,8 @@ public class AtTransaction extends Transaction {
 	public boolean hasValidReference() throws DataException {
 		// Disable reference checking after feature trigger timestamp
 		if (this.atTransactionData.getTimestamp() >= BlockChain.getInstance().getDisableReferenceTimestamp()) {
-			return true;
+			// Allow any non-null value
+			return this.atTransactionData.getReference() != null;
 		}
 
 		// Check reference is correct, using AT account, not transaction creator which is null account
diff --git a/src/main/java/org/qortal/transaction/MessageTransaction.java b/src/main/java/org/qortal/transaction/MessageTransaction.java
index 3a337e96..4540bea6 100644
--- a/src/main/java/org/qortal/transaction/MessageTransaction.java
+++ b/src/main/java/org/qortal/transaction/MessageTransaction.java
@@ -167,7 +167,8 @@ public class MessageTransaction extends Transaction {
 
 		// Disable reference checking after feature trigger timestamp
 		if (this.messageTransactionData.getTimestamp() >= BlockChain.getInstance().getDisableReferenceTimestamp()) {
-			return true;
+			// Allow any non-null value
+			return this.messageTransactionData.getReference() != null;
 		}
 
 		if (this.messageTransactionData.getReference() == null)
diff --git a/src/main/java/org/qortal/transaction/Transaction.java b/src/main/java/org/qortal/transaction/Transaction.java
index 60059163..9f56af6b 100644
--- a/src/main/java/org/qortal/transaction/Transaction.java
+++ b/src/main/java/org/qortal/transaction/Transaction.java
@@ -907,7 +907,8 @@ public abstract class Transaction {
 	public boolean hasValidReference() throws DataException {
 		// Disable reference checking after feature trigger timestamp
 		if (this.transactionData.getTimestamp() >= BlockChain.getInstance().getDisableReferenceTimestamp()) {
-			return true;
+			// Allow any non-null value
+			return this.transactionData.getReference() != null;
 		}
 
 		Account creator = getCreator();
diff --git a/src/test/java/org/qortal/test/TransactionReferenceTests.java b/src/test/java/org/qortal/test/TransactionReferenceTests.java
index a3b24e69..41124649 100644
--- a/src/test/java/org/qortal/test/TransactionReferenceTests.java
+++ b/src/test/java/org/qortal/test/TransactionReferenceTests.java
@@ -80,4 +80,30 @@ public class TransactionReferenceTests extends Common {
         }
     }
 
+    @Test
+    public void testNullReferenceAfterFeatureTrigger() throws DataException {
+        Common.useSettings("test-settings-v2-disable-reference.json");
+        Random random = new Random();
+
+        try (final Repository repository = RepositoryManager.getRepository()) {
+            PrivateKeyAccount alice = Common.getTestAccount(repository, "alice");
+
+            byte[] randomPrivateKey = new byte[32];
+            random.nextBytes(randomPrivateKey);
+            PrivateKeyAccount recipient = new PrivateKeyAccount(repository, randomPrivateKey);
+
+            // Create payment transaction data
+            TransactionData paymentTransactionData = new PaymentTransactionData(TestTransaction.generateBase(alice), recipient.getAddress(), 100000L);
+
+            // Set null reference
+            paymentTransactionData.setReference(null);
+
+            Transaction paymentTransaction = Transaction.fromData(repository, paymentTransactionData);
+
+            // Transaction should be invalid, as we require a non-null reference
+            Transaction.ValidationResult validationResult = paymentTransaction.isValidUnconfirmed();
+            assertEquals(Transaction.ValidationResult.INVALID_REFERENCE, validationResult);
+        }
+    }
+
 }