Comment 25 for bug 1991564

triage-jammy+22.04: ~$ sudo apt-get install dovecot-core=1:2.3.16+dfsg1-3ubuntu2
...
The following additional packages will be installed:
  ssl-cert
Suggested packages:
  dovecot-gssapi dovecot-imapd dovecot-ldap dovecot-lmtpd dovecot-lucene dovecot-managesieved dovecot-mysql
  dovecot-pgsql dovecot-pop3d dovecot-sieve dovecot-solr dovecot-sqlite dovecot-submissiond ntp
The following NEW packages will be installed:
  dovecot-core ssl-cert
...
Created symlink /etc/systemd/system/multi-user.target.wants/dovecot.service → /lib/systemd/system/dovecot.service.
dovecot.socket is a disabled or a static unit not running, not starting it.
Processing triggers for man-db (2.10.2-1) ...
triage-jammy+22.04: ~$ sudo openssl req -new -x509 -days 1000 -nodes -out "/etc/dovecot/dovecot.pem" \
> -keyout "/etc/dovecot/private/dovecot.pem"
............+.........+...............+............+
...
triage-jammy+22.04: ~$ ls -l /etc/dovecot/private/dovecot.pem
ls: cannot access '/etc/dovecot/private/dovecot.pem': Permission denied
triage-jammy+22.04: ~$ ls -l /etc/dovecot/dovecot.pem
-rw-r--r-- 1 root root 1224 May 25 18:50 /etc/dovecot/dovecot.pem
triage-jammy+22.04: ~$ grep /etc/dovecot/private /etc/dovecot/conf.d/10-ssl.conf
ssl_cert = </etc/dovecot/private/dovecot.pem
ssl_key = </etc/dovecot/private/dovecot.key

triage-jammy+22.04: ~$ sudo systemctl stop dovecot.service
triage-jammy+22.04: ~$ sudo systemctl start dovecot.service
triage-jammy+22.04: ~$ sudo doveadm
usage: doveadm [-Dv] [-f <formatter>] <command> [<args>]

  altmove [-u <user>|-A] [-S <socket_path>] [-r] <search query>
...
triage-jammy+22.04: ~$ doveadm
doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 12: ssl_cert: Can't open file /etc/dovecot/private/dovecot.pem: Permission denied
triage-jammy+22.04: ~$

Then testing fixed version after enabling -proposed:

triage-jammy+22.04: ~$ sudo apt-get -y full-upgrade
triage-jammy+22.04: ~$ sudo apt-get install dovecot-core
triage-jammy+22.04: ~$ sudo apt-cache policy dovecot-core
dovecot-core:
  Installed: 1:2.3.16+dfsg1-3ubuntu2.2
  Candidate: 1:2.3.16+dfsg1-3ubuntu2.2
  Version table:
 *** 1:2.3.16+dfsg1-3ubuntu2.2 500
        500 http://archive.ubuntu.com/ubuntu jammy-proposed/main amd64 Packages
        100 /var/lib/dpkg/status
     1:2.3.16+dfsg1-3ubuntu2.1 500
        500 http://archive.ubuntu.com/ubuntu jammy-updates/main amd64 Packages
     1:2.3.16+dfsg1-3ubuntu2 500
        500 http://archive.ubuntu.com/ubuntu jammy/main amd64 Packages
triage-jammy+22.04: ~$ groups
bryce root sudo staff
triage-jammy+22.04: ~$ sudo systemctl stop dovecot.service
triage-jammy+22.04: ~$ sudo systemctl start dovecot.service
triage-jammy+22.04: ~$ doveadm
usage: doveadm [-Dv] [-f <formatter>] <command> [<args>]

  altmove [-u <user>|-A] [-S <socket_path>] [-r] <search query>
...