New Features in 4.2
Features > New Features > New Features in 4.2
New Features in 4.2
The 4.2 version was renamed to 5.0 due to some changes in OpenWire requiring a major version number increase, plus 5.0 being dependent by default on Java 5 to take advantage of the faster and more bug-free java.util.concurrent code.
So please refer to the New Features in 5.0