Hello Sascha @tafkaz,
I do have also doubts about OpenProject on UCS. It seems that there is no real interest to make work this app properly on UCS (although one of the best hosts ever) → https://help.univention.com/t/openproject-removed-from-appcenter-disables-existing-installation/18920 or https://help.univention.com/t/openproject-erlaubt-keinen-login/8228. I wonder if bim@openproject.com does know about the questions on this forum? Thank you for your answer. Greetings Jakob