Overview
- Microsoft, which announced the change Monday, will begin blocking TLS 1.0 and 1.1 on POP and IMAP connections to Exchange Online in July 2026.
- When enforcement begins, POP3 and IMAP4 clients must use TLS 1.2 or newer, the protocol that encrypts email traffic to prevent snooping, or their connections will fail.
- Microsoft says most users already use modern TLS, but customers who opted into legacy endpoints or rely on old or embedded clients risk losing email access.
- Administrators should verify client and library support for TLS 1.2+, update device firmware or application versions, and remove references to legacy endpoints before enforcement.
- The plan follows a 2018 multi-vendor push to retire TLS 1.0/1.1, which date to 1999 and 2006, with The Register noting Google Workspace documentation still lists support for the old versions.