The latest pve-container version 5.3.3 does not only adds the new Ubuntu releases, but for PVE 9 we also defused the hard checks to soft checks, which now only produce a warning in the case an unknown (to new) release is encountered. This was...
The check as it was previously was indeed not ideal, so we not only fixed the issue itself but also changed the check such that it cannot happen in this form again, as now PVE either supports a major Debian release or it doesn't, but no break...
This exactly what happened. Upgraded to debian 13.1 and suddenly stopped running after restarting the container.
Shouldn't happen, should maybe raise a warning but not blocking the start.
This is not a very robust way of doing things Proxmox / @t.lamprecht ...
Stuff like this should soft-fail and not suddenly completly prevent legitimate containers that just have been updated - from being launched with a not so clear error message.