thanks for your feedback!
We just finished porting our largest Kotti app (~50k lines of Python
code plus templates and frontend stuff) and it was also just a matter of
the usual Python 2 to Python 3 porting (strings vs. bytes, etc.).
The low activity on the repo and the long times between releases are
just signs for Kotti being rock solid.
We use Kotti all the time and my company heavily depends on it for the
largest part of our business. So rest assured it will be actively
maintained for a long time.