Ok.
After 2019 releases seems to have died out.
Some of the stuff i think is fixed that was really problematic for me was for example when building it yourself to get support for ca modules built you had to link with a library that just barely built and was normally not included (forgot its name, got a bunch of numbers in it)
Had to first hack together a custom version of dvb-apps with the library included that in turn needed so fixes to build well enough.
Also i think there have been some date/time improvements in the UI since i prefer to stick to english and that unfortunately forces 12h clock and there is no way in tvheadend to adjust it and then stumbled on bug #5292 including its fix (2 years old but not in a release yet)