I believe we are currently on Hibernate 4.2 and we should consider upgrading to Hibernate 4.3 soonish. That way we can stay a bit more current on our implementation of Hibernate and avoid a large upgrade like we had to do a couple of years ago.

Currently there are compile/startup issues with trying to upgrade to the latest version (4.3), but it is undetermined how difficult it will be to fix those issues and if any other issues might occur afterwards.