Hi, we have been using the JMSMessageID to correlate messages in our applications. For example, a client posts a message to the provider and stores the message id. The recieving application will then set the reply message's JMSCorrelationID to the JMSMessageID. With JBossMessaging 1.4.0.CR1 the JMSMessageID seems to change in when the queue is clustered, and the message is moved between nodes. We have previously been running vesion 1.3 and not had this problem. Could you let me know if this is the expected behavior? We can use a custom correlation id to get around this but I've got the impression that using the JMSMessageID to correlate messages is quite common. Thanks, Daniel View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4079850#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...