Push the Kopano LDAP-schema to UCS while not using the Kopano App.
Installing Kopano on a non-UCS system and connecting it to UCS needs the proper Kopano schema on the UCS LDAP.
Simply install the Kopano core packages and remove them afterwards. The Kopano schema will stay installed and you can connect Kopano to UCS LDAP.
univention-app install kopano-core univention-app uninstall kopano-core
Note: Once the Kopano-App will have moved into a Docker container this might not work as expected. Test before implementing then!