It's because of default php versions on Debian:
Debian 10 - php 7.3
Debian 11 - php 7.4
Debian 12 - php 8.2

I'm still on Debian 10 - a new test-install on Debian 12 throws errors when logging in to kolab-webadmin. Didn't investigate further...

Thanks for this happy news :-)

This has now been merged into Kolab:16, though the package is still building, but should become available shortly.

Thx for the News!

Problem is with loading order of php modules. On Ubuntu the fix for me was:

mv /etc/php7.4/cli/conf.d/30-kolabformat.ini /etc/php7.4/cli/conf.d/32-kolabformat.ini
mv /etc/php7.4/apache2/conf.d/30-kolabformat.ini /etc/php7.4/apache2/conf.d/32-kolabformat.ini

We're working on a fix for packaging.

Any further Developments here?