Legacy TLS tour continues with Exchange Online blocking old versions from July 2026

Microsoft has warned users still clinging to legacy TLS versions that the end is nigh for TLS 1.0 and 1.1 on POP3 and IMAP4 connections to Exchange Online.

Redmond warned, "We will start to block legacy version connections starting in July 2026."

The move is long overdue, and the Windows giant has been warning users for years that it was coming. Support for TLS 1.0 and 1.1 in Exchange Online ended in 2020. In 2023, Microsoft announced plans to disable those older TLS versions for POP3 and IMAP4 clients in the name of compliance and security, but acknowledged that there was a "significant" number of POP3/IMAP4 clients that didn't support TLS 1.2 or later, and so added an endpoint for clients to opt to keep using the legacy protocols.

It was, however, very much an opt-in thing, and in July 2026, the time ...