I could not get Folding 7.6.21 to work completely under Ubuntu's current release, 20.04. I backed down to 19.10 which works and for a while still had security updates. Now the security updates have ended. The problem with ubuntu 20.04 I think is that it changed Python versions from 2 in lower versions to 3 in 20.04. I though about changing OS, but found the current versions of Red Hat and Fedora also use Python 3. Are there any plans to migrate the folding software to be compatible with the new Linux/Python versions?
Unfortunately it's not supported like compilers are. If you upgrade C++ (or another language) from version M to version N you'll almost always find that N contains new features but it will still compile code that was written to M's standards. Not so with Python.