post_install() {
  #set up the /var/run directory
  systemd-tmpfiles --create /usr/lib/tmpfiles.d/courier-mta.conf

  # perform all the tasks required of a standard Courier install
  echo Performing install-configure...
  /usr/lib/courier/sysconftool /etc/courier/*.dist > /etc/courier/upgrade-$1.log
  echo ...output saved to /etc/courier/upgrade-$1.log
  echo "Do not forget to choose an account to receive postmaster mail."
  makealiases
  makesmtpaccess
  /usr/bin/mkdhparams
}

pre_upgrade() {
  # the file courier-imapd.conf is renamed to courier-mta.conf for version 0.77.0-2
  [ -f /usr/lib/tmpfiles.d/courier-imapd.conf ] && rm -f /usr/lib/tmpfiles.d/courier-imapd.conf
}

post_upgrade() {
  echo Performing install-configure...
  /usr/lib/courier/sysconftool /etc/courier/*.dist > /etc/courier/upgrade-$1.log
  echo ...output saved to /etc/courier/upgrade-$1.log
}

pre_remove() {
  # there may be many files not part of the original installation that would be useful to save
  # so save the whole configuration directory rather than try to list all possibilities
  # in backup(). Also avoids creation of .pacsave files in alias and smtpaccess directories that
  # process all files
  mv -f /etc/courier /etc/courier-$1
  cat << EOM
 --> /etc/courier has been saved as /etc/courier-$1
EOM

  # clean up the /run and /var/spool directories
  systemd-tmpfiles --remove /usr/lib/tmpfiles.d/courier-mta.conf
}