Context: in May 2023, Tiki trunk/master changed requirements from PHP 7.4 to 8.1. So if you have some Tiki instances running trunk/master with Virtualmin Tiki Manager, they will not upgrade automatically. Here is what you must do:
If you are running trunk/master, you are likely in a development context, and if you want error messages displayed:
cd /opt/tiki-manager/app
php tiki-manager instance:edit
To do: explore if php tiki-manager instance:detect
could be improved to handle this
GUI: Services -> Tiki Manager -> Instance Update -> Update
As of 2023-05-20, you may get an error
Updating Tiki Packages... [may take a while] [ERROR] Failed to update Tiki Packages. Check /opt/tiki-manager/app/logs/trim.output for more details
This will be solved shortly.