What versions of linux distros are AppImages able to run on?

I found this refrence: Testing your AppImage — AppImage documentation
But I believe its old because the newest Fedora version supported according to it is 27. Is there a more updated list of what distros and versions support AppImages or do y’all just kind of guess?

It depends what you put inside the AppImage. (AppImage is just a self-mounting disk image that executes whatever the author has put inside.)

We are generally recommending to test your AppImages on the oldest still-supported LTS release of Ubuntu.

We are assuming that every application that can run there should be able to run on any newer Linux distribution as well.

If you want to be sure, then you need to test it.

If something runs on the oldest still-supported LTS release of Ubuntu but not on a newer Linux distribution, then that never Linux distribution is not fully binary compatible; it’s maybe a bug that should be reported to them.