I though that implicit TLS was evil, (port 465 for SMTP submission was
revoked) and STARTTLS encouraged.
But I read a new RFC that promotes implicit TLS as a recommended access.
Uhm... If I well understood, new SMTP,POP,IMAP services should offer
implicit TLS as a favourite TLS negotiation.
Anyway I hope that new versions of Perdition could support the
STARTTLS/STLS for many years ;)