Yup that pretty much sums it up. Concurrent updates will be dealt with exactly as they are dealt with right now. Regarding releasing, it is easier than you think: DataVersions were a strictly Optimistic-Locking feature. With MVCC, we never made any promises that DataVersions would apply. Just as we ignore custom data versions with Pessimistic Locking, I expect to do the same with MVCC. The problem with leaving versioning logic in MVCC is that it is pretty central. (Use VersionedNode instead of UnversionedNode, different write-skew check, different ways of handing custom data versions which may be unnecessary). I'd rather we leave this out (if the logic makes sense) and move on from a fragile and broken API. :-) View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4163933#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...