Microsoft will start blocking legacy TLS 1.0 and TLS 1.1 connections for POP and IMAP email clients in Exchange Online beginning in July 2026. Most users running modern clients that support TLS 1.2 or later won’t be affected, but legacy devices and custom applications must be updated or they will fail to connect. #ExchangeOnline #TLS1.2
Keypoints
- Microsoft will deprecate TLS 1.0 and TLS 1.1 for POP3 and IMAP4 in Exchange Online starting July 2026.
- POP and IMAP connections will require TLS 1.2 or later and connections using legacy TLS will fail.
- Most modern email clients already use TLS 1.2+, so the majority of users are unlikely to be impacted.
- Legacy devices, embedded systems, and custom applications may stop connecting and will need updates.
- Customers should check client configurations and work with vendors to ensure TLS 1.2+ support to avoid disruptions.