instead of just smtp:// with STARTTLS.
Opted to call the flag --ssl and not --tls to keep it consistent with
the module option (mailserver.enableSubmissionSsl), dovecot internals
and smtplib in mail-check.py.
With upcoming changes to the dovecot home and maildirectories we need to
introduce a way to nudge users to inform themselves about manual
migration steps they might need to carry out.
The idea here is to allow us to safely make breaking changes and notify
the user of required migration steps at eval time, so they can make the
necessary changes in time.
