on Tuesday 2020-12-01 we'll migrate our mail server again.
This time we'll change the following:
- disable IMAP on Port 143
- disable POP3 on Port 110
- enable SMTPS on Port 465
Note: IMAPS (993), POP3S (995) and Submission (587) is not going away
with this change.
Please check your setup, that it's not using either Port 110 nor 143.
For the future, there are plans to deprecate Submission port 587, so
feel free to use port 465 asap.