I've upgraded from Debian11 to Debian12 (bookworm( with the Testing-Repo added.
The good news is that sending and receiving mail works well. I'm struggeling with roundcube (my users access with snappymail - that works) and webadmin.
Let's have a look at webadmin:
# dpkg -l kolab-webadmin ... ii kolab-webadmin 3.2.16-0~kolab2 all Kolab administration web interface
The first thing I noticed is that 3.2.26 has been release in 2021:
Tag: kolab-webadmin-3.2.16 d2f531414aa7·Release 3.2.16·machniak on Nov 8 2021, 14:11.
In the meantime there have been lot's of changes, e.g. php8 fixes. I think it's time to cut a new release.
[currently the git history in phabricator is broken...]
The Debian packages has these dependencies:
Depends: apache2, libapache2-mod-php | libapache2-mod-php5, ldap-utils, php-http-request2, php-mail, php-net-ldap2, php-net-ldap3, php-net-smtp, php-net-url2, php | php5, php-mysql | php5-mysql, smarty3 (>= 3.1.7)
Since php5 is long gone, these dependencies should be removed.
I'm also unsure why both php-net-ldap2 and php-net-ldap3 are needed.
It might also be useful to move to smarty4.