Well,
I copied my old instance volumes locally and started it fully functional (still on 11820a4d3a89cac23741932f128724852def6aac revision) with old docker-compose binary 1.29.2.
On my up-to-date system (Docker 25.0.4 + Compose plugin 2.24.7), I launched ./update.sh:
$ ./update.sh
Checking internet connection... OK
Checking for newer update script...
Updated 1 path from 12754a3b
update.sh changed, please run this script again, exiting.
Second launch:
$ ./update.sh --stable
WARNING: Please see on GitHub or ask in the communitys if a switch to master is stable or not.
In some rear cases a Update back to master can destroy your mailcow configuration in case of Database Upgrades etc.
Normally a upgrade back to master should be safe during each full release.
Check GitHub for Database Changes and Update only if there similar to the full release!
Are you sure you that want to continue upgrading to the stable (master) branch? [y/N] y
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And… It worked.
I’m now on 2024-02 release. All containers are started. The service seems to be fully functional. I found my domains and mail boxes back. Emails are still there. Solr search is working.
My vmail volume was much lighter than the real one (10%). But I do not think it would make a big difference.