The release version number in jbossmessaging-version.properties was not incremented from beta3 to beta4, they both use the same value 104. :( This means the version check code is now useless, and the server will allow b3 and b4 clients and servers to try to connect, and all sorts of weird things to happen, and it makes it difficult to track down errors related to different versions of clients and servers. It's very important the version number is incremented on each release. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4247656#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...