There is a clear plan to enhance the JMS specification and that is JMS 2.1 (JSR 368), slated for inclusion in Java EE 8. The JMS 2.1 Expert Group is still in formation phase and once this is done, the EG will start the actual works on the next revision of JMS. This work is expected to take time, Q3 2016 is the current ETA for the Java EE 8 final release.
But let's not forget the current version of JMS, i.e. JMS 2.0 (JSR 343). An errata is needed to correct a few errors in JMS 2.0 which can't wait for JMS 2.1 because they affect the ability of implementers to correctly implement JMS 2.0 today. An 'errata' is a simple kind of maintenance release intended purely to correct errors in the specification, so clearly the intention is not define any new features (any new features should be discussed within the JMS 2.1 scope).
For that reason, Nigel Deakin (JMS 2.0 and JMS 2.1 Specification Lead) has proposed and started an errata for JMS 2.0. An Errata release (and maintenance releases in general) don’t have an Expert Group. Nevertheless Nigel is soliciting feedback on the various small issues that he plans to have addressed in the JMS 2.0 Errata. You can check the changes proposed for the JMS 2.0 errata on this Wiki page, the jms-spec users mailing list is a good channel to provide feedback.
