diff --git a/CHANGES.txt b/CHANGES.txt
index fcebd17092..d6d2117dd9 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -1,4 +1,6 @@
 4.0-beta5
+ * Fix 4.0 node sending a repair prepare message to a 3.x node breaking the connection
+   (CASSANDRA-16542)
  * Removed synchronized modifier from StreamSession#onChannelClose to prevent deadlocking on flush (CASSANDRA-15892)
  * Throw IOE in AbstractType.writeValue if value has wrong fixed length (CASSANDRA-16500)
  * Execute background refreshing of auth caches on a dedicated executor (CASSANDRA-15177)
diff --git a/src/java/org/apache/cassandra/repair/messages/PrepareMessage.java b/src/java/org/apache/cassandra/repair/messages/PrepareMessage.java
index 9c485bc2f1..7c8db93222 100644
--- a/src/java/org/apache/cassandra/repair/messages/PrepareMessage.java
+++ b/src/java/org/apache/cassandra/repair/messages/PrepareMessage.java
@@ -130,8 +130,6 @@ public class PrepareMessage extends RepairMessage
 
         public long serializedSize(PrepareMessage message, int version)
         {
-            Preconditions.checkArgument(version == MessagingService.current_version, MIXED_MODE_ERROR);
-
             long size;
             size = TypeSizes.sizeof(message.tableIds.size());
             for (TableId tableId : message.tableIds)