I think it would be pretty heavy to have to check a version on every interface (in this model, an interface is not just a java interface as described previously) - The CommonVersion class might work but you still need to ensure it gets loaded before _other_ actual (common) interfaces; otherwise you could still get into a situation where version check would not happen, leading to unexpected (interface) errors as some of the interfaces could be accessed very early on during start-up. Not a blocker I think, just pointing that out...

--francois