From dev blog (1st July).
"In the meantime, though, I think it’s time for a bit of a break. I’ve been working on RimWorld and its prototypes for going on three years straight now, and my hours are usually pretty long. I’m starting to feel a bit of burnout. I often seem to develop this dull ache behind the eyes after a couple hours of work. I have trouble concentrating for the lengths of time that used to be normal for me. For that reason – and just because I believe in having a life that isn’t all work – I’m taking some time off from full-time RimWorld development starting in September. Currently it’s looking like it’ll be about six months. I’ll still be around to interact, but I won’t be developing constantly like I have been."
I'd call development paused,it sounds less final than stopped.