Please set "subscriptions = yes" in /etc/univention/templates/files/etc/dovecot/conf.d/10-mail.conf as default:


print("  location = maildir:%%%%h/Maildir:INDEXPVT=%s/shared/%%%%u%s" % (index, control))
@!@

  ### here is the change.
  subscriptions = yes

  # List the shared/ namespace only if there are visible shared mailboxes.
  list = children
}

# a separate namespace for each public (admin managed) mailbox
@!@


so all by users shared mailboxes are accessible via IMAP and configuration needs no further adjustment.

Thank you.