I had the same email sent from [email protected]
The links just took you to videos and instruction how to change ports and the reason why they are doing it (for tighter security) and from Dec 2026 the old ports will not work.
It looked official and the ports (some were the same, some were different) did not conflict with what BT site was saying.
It would still be nice to know if this was spam/scam.
Thank you Peter
Just seen your reply and feel reassured the email (from [email protected]) is correct and not spam/scam.
Regardless of whether the email was spam/scam, there is no way in 2026 you should be using insecure ports.
As posted before the ports that you should be using are
SMTP 465 with SSL/TLS
IMAP 993 with SSL/TLS
POP3 995 with SSL/TLS
If your client is configured differently, change to those ports.