See the release notes: https://forum.virtualmin.com/t/virtualmin-install-sh-support-for-centos-8
For PHP, FCGId is deprecated on CentOS 8 (because we no longer provide a custom Apache package, so there is no working suexec). The only currently supported way to run PHP is FPM. This is what’s recommended by the upstream PHP folks, so we’re just going along with that. It’s still plausible we’ll come back around to believing we need suexec, but I’m not convinced of that, so far. There are ways to use it even without a custom build, but I don’t really like any of them (bind mounting home over /var/www is one).
But, PHP-FPM not working out of the box is a serious issue, though I don’t know that we’ve had bug reports about it and it didn’t show up in our testing. I’ll have to try to replicate that.
I’m not sure about DAV. It’s been a long time since I looked at it, since the Apache implementation is kinda crap and doesn’t really work in the real world for most people. What specifically are you doing with DAV? If it worked in the past, we’d like it to continue to work, and I don’t know, off-hand, any reason it wouldn’t…so, it’s maybe something we can fix, even if we aren’t spending a lot of effort on DAV.