Debian 10 has been stable for a little while now, and Debian 8 is nearing end of life. We really should be supporting Debian 10 now.
What are the known problems? Just the one in bug 23799?
I think this bug is meant to serve as a collector.. right now the packaging is the biggest issue and Mason has been working on that for us.. Once we have packages that build at all, we can run the test suit against it more thorough and find other possible issues.. I'm envisaging a few DB issues as newer Debian comes with newer MariaDB and perhaps some other dependency problems.
All dependent bugs have been resolved and we are already listing Debian 10 and 11 on the requirements page: https://wiki.koha-community.org/wiki/System_requirements_and_recommendations Closing this one.