We've been working on Subrion 2.2.0 for the past few months and finally we are satisfied with the work we've done so far. Subrion 2.2.0 is more a stability update. It does not include too many new features, but it has tons of internal changes that allow to develop plugins & templates for the software much faster. The most significant change is the Bootstrap implementation. Below you can find the list of changes implemented in our version.
Your questions are welcomed in the Subrion CMS User Forums.