Wouldn't that be an arbitrary decision?
EJB had their chance to make a lot of improvements between 1.1 and 2.0
If we take too hard on compatibilities, we make take the risk in JMS2
becoming 1.2, 1.3... etc.
And I think the idea is JMS *2.0*
We could still have the old model, and create a new package for new
applications, just like EJB 2 had done in the past.
JMS is a pretty old spec. We could do a lot of improvements on it with
current API standards.. etc