Hibernate Core 4.0.0.CR3 has just been released. The complete list of changes can be found in the JIRA release notes.
This release contains some changes to integration SPIs (for Hibernate OGM, Hibernate Spatial, etc) that we wanted to make sure made their way into 4.0. See HHH-6091 and HHH-6640 in particular. There are bug fixes as well.