since long, long time, I have had no trouble with update in NC.
My Nextcloud is hosted by an IT provider.
Make upgrade 27 → 28 no problem. Next upgrade: 28.0.14.1, → 29.0.12
after this information:
Reparaturinformation: Change collation for nc_4371_login_ips_aggregated …
get a Information
“Es ist ein Fehler aufgetreten.”
and NC switched to Maintenance = "true"
After change the settings, Maintenance = "false"
Nextcloud is going to
It would also be helpful if you shared your configuration (as also noted in the support template) since the error is related to your collation/database configuration.
Are you doing the entire update/upgrade from the web UI? Have you attempted doing from the command-line to see if more information is shown?