The upgrade of OpenProject to version 10.x fails with an SQL error.
UCS 4.x with OpenProject App in version 9.x installed. The server in question has been installed initially as UCS 4.2 or earlier.
The upgrade to verson 10.x of the app will fail and you will see an error as shown:
Caused by: PG::SyntaxError: FEHLER: Syntaxfehler bei »ON« LINE 20: ON CONFLICT (from_id, to_id, hierarchy, relates, dup... [...] Rebuild DAG migration failed. See above. Failed to migrate MySQL to Postgres App upgrade script failed Aborting... Starting docker-app-openproject (via systemctl): docker-app-openproject.service.
OpenProject 10.x requires at least PostgreSQL version 9.5. As the PostgreSQL databas is not upgraded automatically on UCS you probably have version 9.4 or earlier installed. Upgrade to v9.6 as shown here and restart the upgrade of your app afterwards.