Here is the list of the major accomplishments embodied in 3.5.0-Final
- JSR 317 (JPA2) support.
- Integration of hibernate-annotations, hibernate-entitymanager and hibernate-envers into the core project. See http://in.relation.to/14172.lace for details
- Added Infinispan as a standard second-level cache. See http://infinispan.blogspot.com/2009/10/infinispan-based-hibernate-cache.html for details
- Improvements to the new second-level caching SPI introduced in 3.3 based on feedback from implementers including Ehcache, Inifinispan and JBoss Cache.
- Far better
immutablesupport. See the new chapter added to the core reference manual dedicated to the subject.
- Support for JDBC 4 such that Hibernate can be used in JDK 1.6 JVMs and make use of JDBC4-compliant drivers.'
- Support for column-level read/write fragments (HBM only for now)
- Initial support for fetch profiles
Check out the release page for the full list of changes (just in 3.5.0-Final, aka not cumulative).
you can see http://relation.to/15040.lace for details.