After finally working around the 389-ds package breakages in the 18.04 to 20.04 upgrade process described here: https://git.kolab.org/T8379 I discovered that a number of necessary kolab packages are not in any repo newer than 18.04. I was able to grab them from the debian 12 repo and they "work" but these packages need to be built for newer Ubuntu as their absence keeps installs on 18.04 with is EOL. The missing packages are:
kolab-cli kolab-conf kolab-saslauthd kolab-server kolab-xml pykolab wallace