Fixed it.
after reupdating i found this in the logs:
Sep 22 21:02:29 ucs postmulti[25319]: fatal: instance /etc/postfix, shlib_directory=/usr/lib/postfix conflicts with instance /etc/postfix, daemon_directory=/usr/lib/postfix
So all i had to do was:
postconf -e daemon_directory='/usr/lib/postfix/sbin'
postconf -e shlib_directory='/usr/lib/postfix'
postconf -e compatibility_level=2
for i in $(postconf -Mf | grep '^[0-9a-zA-Z]' | awk '{print $1"/"$2"/chroot=n"}'); do postconf -F $i; done
solution found here:
https://docs.iredmail.org/upgrade.debian.8-9.html
are these changes now updatesafe, or would i better change something in some templates again?
And how the hell was this ṕossible to be happening in the first place?
Shouldn’t univention-upgrade take care of these changes?
thanks
Sascha