Stuck in unintended direct update from 20 to 22 on Synology docker

OS: DSM 6.2.4-25556
It seems that my docker installation on Synology diskstation is stuck, because watchtower downloaded version 22 while I espected 21 for a smooth one-step update.
Is there any easy way to overcome that?
I thought I could switch image from nextcloud:latest to nextcloud:21 somehow but that is not offered. With my restricted experience I do not see a simple procedure.
Any recommendations?

These are my findings with occ

www-data@nextcloud1:~/html$ ./occ status
Nextcloud or one of the apps require upgrade - only a limited number of commands are available
You may use your browser or the occ upgrade command to do the upgrade.

  • installed: true
  • version: 22.0.0.11
  • versionstring: 22.0.0
  • edition:

www-data@nextcloud1:~/html$ ./occ upgrade
Nextcloud or one of the apps require upgrade - only a limited number of commands are available
You may use your browser or the occ upgrade command to do the upgrade
Setting log level to debug
Exception: Updates between multiple major versions and downgrades are unsupported.
Update failed

www-data@nextcloud1:~/html$ ./occ config:list
Nextcloud or one of the apps require upgrade - only a limited number of commands are available
You may use your browser or the occ upgrade command to do the upgrade
….
“datadirectory”: “REMOVED SENSITIVE VALUE”,
“dbtype”: “mysql”,
“version”: “20.0.6.1”,