Errors after freebsd upgrade

[Hanns Mattes]

Hi,

after upgrading Freebsd from ports dovecot is throwing the following error

Oct 30 18:04:15 freebsd dovecot[59232]:
doveadm(xxx at example.com)<84061><S3CoJf9sfWFdSAEAUmejdw>: Fatal: master:
service(doveadm): child 84061 killed with signal 6 (core not dumped -
https://dovecot.org/bugreport.html#coredumps - set service doveadm {
drop_priv_before_exec=yes })

I (surely) may have missed something while upgrading (I've learned a lot
about backup/snapshot-strategies with zfs, but to late to apply).

How can I debug the erro?

Regards Hanns