Bela - the compatibility matrix indicates that you don't need the -Djgroups.marshalling.compatible=true property setting if you're running JGroups 2.4.x with JBossAS 4.0.5.GA. It does note that earlier versions of JBossAS require the setting. We're planning to use JGroups 2.4.1-SP1 with JBossAS 4.0.5.GA so we're interested in whether this setting is required. Jerry View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4034515#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...