Hibernate ORM version 4.1.7 has just been released. This is a bug fix release containing 27 fixes. See the changelog for the complete list of fixes. Again, 4.1.7 benefited from a lot of community involvement. We really appreciate all the help in terms of pull requests, testing, comments, ideas, etc.
4.0 changes the way event listeners get registered to leverage some added capabilities, namely services and integrators. I won't get into services too much as they are covered elsewhere. But lets start with the notion of an Integrator.