I just did this for 4.3.10 -> 4.4.x.
For now (only going to last a few months) the upgrade path is:
- standalone engine: pivot to a CentOS 8.4 VM - backup and restore method; decommission EL7 engine
- standalone engine: before upgrading your hosts set firewall management method to "firewalld". If you do not
do this you will not see any network interfaces at your hosts ("Setup Host Networks" page)
- hosts: pivot to CentOS Stream 8 - nuke-n-pave your existing hosts in a rolling upgrade method
For engine, if you choose to use a EL8-rebuild (OL8, Rocky Linux 8, AlmaLinux 8) you will need to
set OTOPI_DNF_ENABLE=1 if engine-setup fails with a miniyum error (this means that it failed to detect
a dnf-capable system).