Hi John, JBossMessaging depends on Remoting 2.2.0, and JBoss ESB depends on JBM. They argued in favor of JBossAS 4.2 adopting Remoting 2.2.0 to avoid scoping in JBM, and they carried the day. The original release of Remoting 2.2.0 was not wire compatible with 2.0.0, and the point of 2.2.0.SP4 was to compensate for that incompatibility. A client or server running 2.2.0.SP4 can be configured to talk to version 2.0.0 by setting the system property "jboss.remoting.version", in particular, -Djboss.remoting.version=2. The 2.2.0.SP4 jboss-remoting.jar can be found at http://repository.jboss.com/jboss/remoting/2.2.0.SP4/lib/. -Ron View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4045207#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...