@Dominique I can’t promise that, no.
1.5.10 is the original release, and it is a long way behind now. It was built and tested against PHP 7.x. It may run fine on PHP 8, but I don’t know which PHP 8 version, if any, would be safe for it.
What we do know works on PHP 8 is the current stable branch. Here is how the branches fit together:
master is the official 1.5.10 release. We don’t work on it directly.
dev-branch is where all the bug fixes and maintenance happen.
stable gets everything from dev-branch rolled into it once a month.
So stable is 1.5.10 plus a few years of fixes, PHP 8 support among them.
If you want to move to PHP 8 before 1.6.0 comes out, I’d do it in this order:
Snapshot the server first, so you can roll back.
Update FOG to the stable branch and run the installer. Do this while you are still on PHP 7.2.
Then move PHP to 8.2. On Red Hat 8 the installer will not do that for you; it installs whichever PHP module is enabled. Run dnf module reset php then dnf module enable php:8.2, then dnf distro-sync.
Re-run the FOG installer, so it picks up the new PHP packages.
Test the web console, a host registration, and a unicast and a multicast deploy before you call it done.
Since this is production, your plan to wait for 1.6.0 and try the RC in a test environment first is a good one too.