I am running 2.13.5 on a fully up to date 18.04 ubuntu install.
I installed v2 from source and have been updating via git.
I’ve tried running the Ubuntu upgrade from 18.04 to 20.04 and then running the package migration and end up with either a 502 nginx error, the default nginx welcome screen or a fully unresponsive web host.
I also tried spinning up an entirely new 20.04 host and installed v3. I migrated my my config file, GPG server key and imported an export of my database then ran the database migration with similar results.