3.0.11 is the 3.0.x branch which is used by the newly released EAP 6 / JBoss 7.x application server. It consists mainly of bug fixes (and one or two performance enhancements) backported from the 3.1 branch.
The 3.1.0 release has 90+ issues which were resolved (some of them backported to 3.0.x).
Here's a short list of the major issues resolved in 3.1.0, for details consult :
- NAKACK, UNICAST and NAKACK2 now use a new internal data structure for message delivery and retransmission, which reduces the memory needed by JGroups
- MERGE3: a new merge protocol for large clusters
- RSVP: blocks the sender until a given message has been received by all members of the target set
- A new Total Order Anycast (TOA) protocol needed by the next version of Infinispan to deliver messages to a cluster subset in total order
- New discovery protocols for mod-cluster (not yet completely done), Rackspace and OpenStack
- MPerf / UPerf: dynamic multicast and unicast performance tests
- Concurrent joins to a non-existing cluster are faster, and there's less chances of a merge happening (optimization)
- TCP: socket creation doesn't block sending of regular messages (optimization)
As usual, use the mailing lists or fora for questions.