New opt-in endpoint for POP3/IMAP4 clients that need legacy TLS

tvanscot GrahamCleary Please check out the post that was published earlier, when we announced legacy TLS versions deprecation, related section is pasted below. Besides this guidance, there is no other logging feature that we are aware of, that can help M365/EXO customers with this task. HTH.

Exchange Server TLS guidance Part 2: Enabling TLS 1.2 and Identifying Clients Not Using It - Microsoft Community Hub

POP/IMAP

No logging exists which will expose the encryption protocol version used for POP & IMAP clients. To capture this information, you may need to capture netmon logs from your server or inspect traffic as it flows through your load balancer or firewall where HTTPS bridging is taking place.