On 2020-10-06 11:15:57 +0300 (+0300), Marios Andreou wrote: [...]
main reason for keeping queens is because it is part of the fast forward upgrade (ffu) ... i.e. newton->queens for ffu 1 and then queens->train for ffu 2. So indeed the backports will go as you described - to train then queens
[...]
Previous discussions highlighted the need for all stable release branches newer than a particular branch to have at least the same level of support or higher. This expectation was encoded into the Stable Branches chapter of the Project Team Guide:
https://docs.openstack.org/project-team-guide/stable-branches.html#processes
Further, fast forward upgrades aren't designed the way you're suggesting. You're expected to install each version of the software, so to go from Newton to Queens you need to install Ocata and Pike along the way to do the necessary upgrade steps, and then between Queens and Train you need to upgrade through Rocky and Stein. What's unique about FFU is simply that you don't need to start any services from the intermediate branch deployments, so the upgrades are performed "offline" so to speak.
Granted, no TripleO deliverables have the stable:follows-policy tag, so as long as you're only referring to which branches of TripleO repositories are switching to EOL you can probably do whatever you want (assuming the TC doesn't object). If TripleO's upgrade orchestration in stable/train is able to perform the Rocky and Stein intermediate deployments, it would presumably work. The service projects don't have the same luxury however, and so can only EOL a particular stable branch if all older branches are already EOL.