We are using Hibernate 4.0.0.Alpha3, previously we used Hibernate 3.6.1 (and 3.6.4 for one day). The current plan is to upgrade to Hibernate 4.0.0.Beta1 in two weeks. Check out http://relation.to/Bloggers/HibernateCore400Alpha3Release for more information about this new Hibernate release. We also recently upgraded from Infinispan 5.0.0.CR1 to 5.0.0.CR2. Some notes on Infinispan 5.0.0.CR2 are here http://planet.jboss.org/post/infinispan_5_0_0_cr2_pagoa_released Yesterday, we also upgraded JBossTS to 4.15.0.Final. See http://jbossts.blogspot.com/ (blog entry on "April 26, 2011"). Scott