The freeware Rotorsim/HSF EC-135 went through a major update with nearly 50 improvements, additions or fixes, which you can follow on the changelog.
The EC-135 comes in 3 flavors: free, plus or pro and, despite the differences between the 3 versions, there are now more common parts as well, which should help the team maintain the project in the future.
You can get the new version of the EC-135 at the Rotorsim.de website.