Microsoft announced that Exchange Web Services (EWS) for Exchange Online will be shut down on April 1, 2027, with default blocking beginning October 1, 2026 and no exceptions after the final cutoff. Administrators can temporarily preserve access by configuring application allowlists by the end of August 2026, Microsoft will pre-populate allowlists in September 2026 for tenants that do not create their own, may run temporary “scream tests” to expose hidden dependencies, and recommends migrating apps to the Microsoft Graph API. #ExchangeWebServices #MicrosoftGraph
Keypoints
- Microsoft will block Exchange Online EWS by default on October 1, 2026, and fully retire it on April 1, 2027.
- Administrators who configure application allowlists by the end of August 2026 will be excluded from the automatic October blocking.
- Microsoft will pre-populate allowlists for tenants that do not create their own starting in September 2026 and may run temporary “scream tests” to reveal hidden dependencies.
- EWS will continue to function in on-premises Exchange Server installations, but cloud mailboxes must move to Microsoft Graph.
- Developers are advised to migrate EWS-based applications to the Microsoft Graph API, which now offers near-complete feature parity for most scenarios.