K2 is actively developed. See the commits in the codebase here:
github.com/getk2/k2/commits/master
We're just bad at marketing :)
The next release is K2 v2.10 and will come early next week (after much delay indeed). After that, there will be a change in the site to emphasize that K2 is actually based on the rolling-release model, aka software that gets updated weekly or even daily. In that state, there will come updates with a versioning scheme that moves fast (e.g. v2.10.14) with a dedicated area on getk2.org to highlight any changes, instead of formal lengthy blog posts (which I've come to hate by the way).
