MC1293480 (Updated) Exchange Online: Retirement of legacy TLS versions for POP and IMAP connections
Updated July 7, 2026: We have updated the timeline. Thank you for your patience. [Introduction] We are retiring support for legacy Transport Layer Security (TLS) versions for POP3 and IMAP4 connections to Exchange Online. This change improves security and aligns with current industry standards. TLS 1.0 and TLS 1.1 are no longer considered secure. Most modern email clients already use TLS 1.2 or later. [When this will happen] Rollout start: August 1, 2026 Rollout end: December 31, 2026 The rollout will occur gradually worldwide. [How this affects your organization] Who is affected Microsoft 365 tenants using POP3 or IMAP4 with Exchange Online Admins managing email clients, applications, or devices that use POP or IMAP What will happen POP3 and IMAP4 connections will require TLS 1.2 or later. Connections using TLS 1.0 or TLS 1.1 will fail. Modern email clients are not expected to be affect