Table "groups" in otrs is now a reserved word for mysql 8, so upgrading from ubuntu 18.04 to 20.04 "dies" in the middle of the process because otrs package cannot update its tables.
This bug is related to bug 1953033
There is a workaround though that has been filed here: https://github.com/znuny/Znuny/commit/fafd56a8671e5a9f63f7f75278aaaadcedb01838 and "saved" my ticketing system...
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ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu27.21
Architecture: amd64
CasperMD5CheckResult: skip
DistroRelease: Ubuntu 20.04
InstallationDate: Installed on 2013-03-22 (3187 days ago)
InstallationMedia: Ubuntu-Server 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120817.3)
PackageArchitecture: all
ProcEnviron:
TERM=xterm-256color
PATH=(custom, no user)
LANG=it_IT.UTF-8
SHELL=/bin/bash
ProcVersionSignature: Ubuntu 5.4.0-91.102-generic 5.4.151
Tags: focal third-party-packages
Uname: Linux 5.4.0-91-generic x86_64
UpgradeStatus: Upgraded to focal on 2021-12-02 (10 days ago)
UserGroups: N/A
_MarkForUpload: True
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