I'm working on packaging JBoss for Gentoo Linux. The most recent version we have in portage is 3.2.5. My question is this: what level (if any) of compatibility is there between 3.2 and 4.0? This is in terms of library compatibilty (things that compile against jboss's jar files) and application compatibilty (ie, use war/ear files that worked in 3.2 in 4.0 without modification).