Exchange Online EWS, Your Time is Almost Up

Microsoft is retiring Exchange Web Services (EWS) in Exchange Online due to security and modernization needs. The EWS retirement plan begins in October 2026, marking the start of a phased disablement process. Administrators need to prepare by evaluating EWS usage and planning migration to Microsoft Graph. EWS will be disabled by default in October 2026, unless an Allow List is configured. Admins can maintain EWS access by setting EWSEnabled to True and managing an Allow List. A new feature will allow admins to define an AppID Allow List to control EWS access. In September 2026, Microsoft will auto-populate Allow Lists based on existing usage for tenants who haven't created their own. The final EWS shutdown is scheduled for April 1, 2027, after which it will be permanently disabled. This change impacts Microsoft 365 and Exchange Online only, not on-premises Exchange Servers. Monthly updates and potential "scream tests" will be provided to keep admins informed.