At least in the passt this was more like a rolling release on upstream side, but haven't closely followed the recent developments. However since we cannot lock down specific versions anyways since by design everytime the valheim server restarts, it checks and may or may not update itself, we can also not really release new package versions on our side as they become meaningless. The whole valheim server/client contract seems to be evergreen.
So essentially as soon as the game client reports old server version, just restart that valheim app on your cloudron and it should be on latest again.