I work on an inherited project, old enough to use EJB 2.1 and JBoss 4 (some version). We now want to move on to JBoss 7.1.1 but perserve the EJB 2.1 implementations (there would be too many changes to make). Is JBoss 7.1.1 compatible with EJB 2.1 ?
It has compatability with EJB-2.x as specified in AS 7.1.0 final release notes for Java EE 6 full profile :
EJB 3.1 Full - Adds a number of key features, including remote communication, asynchronous method invocation, timers, message-driven beans, and legacy compatibility with EJB 2.
It remains same for JBoss AS 7.1.1 as it is a maintainence update to JBoss AS 7.1.0.