JBoss has announced the release of JGroups 2.4. "Over 80 JIRA issues were resolved in 2.4, mostly bug fixes and new functionality. The good news is that 2.4 is API-backward compatible with all previous versions down to and including 2.2.7. So, for those folks who are using JBoss 4.0.x, which ships with JGroups 2.2.7 by default, this means that they can simply replace their JGroups JAR file with the one from 2.4 and benefit from the performance enhancements and bug fixes that went into 2.4."