The current version is the most stable release, however the game is updated a lot on the next_version branch, which you can access by going into steam and right-clicking offworld -> proprties -> beta's -> enter the code MohicanSun2015
Also Soren, Mohawks CEO, was busy at GDC for a while so progress has been slow lately. Don't expect much major content added before release however, it's mostly balance changes and extra game options. I believe there's some extra character variants in the works for the campaign though.
