Its nearly four years now since the last release and a lot of things has happened since there, the most notables are:
the UI was reworked to allow more work in the Main Perspective
lots of APIs have be improved and added making it even more flexible and easy to extend
we have joined repositories and moved to github to allow easier contribution and development
But there are still lots of things to do, for example support of newer java and eclipse versions. To accommodate for this, we are preparing a new release now to get some kind of baseline we can build on to improve the whole release-process. One major goal is to be prepared to join the sim-rel train, so continuous improvement as well as stable versions are released on a regular basis.