It is still being tested…
But it definitely makes a difference if Kopano has always and exclusively been installed from the Univention repositories or if Kopano was also updated from the Kopano repositories under UCS 4.4.
When upgrading to UCS 5.0, Kopano core, Kopano webapp, z-Push and univention-appcenter-docker are removed. Kopano can then “mostly” also no longer be installed via the UMC. Only after “apt-get install univention-appcenter-docker” has been executed, the Kopano and Z-Push apps can be installed again.
After that everything should run and work again.
Would be great if someone could test this.