The team has been working on the new version for quite some time and they have finally released a test build for users to try and give their feedback.
There's not a lot of information regarding the features on the EC-145 v4.0 alpha (it's not even a beta so do expect some bugs and unfinished features). The model seems a bit different on some areas (which need some work) but the main differences lie on the flight dynamics.
The team does warn, though: you will need to boost the "flight models per frame" setting to some CPU-thirsty 7, which makes the model a bit too power-hungry, perhaps? It's still an alpha, so a lot can change meanwhile.
If you're up to try it out, head off to RotorSim's website and get this build. Please note that the page is in German (there's no English version) but you will find the link to download it there.