Starting in October 2026, Microsoft will roll out a phased plan to phase out Exchange Web Services (EWS) in Exchange Online. Administrators will have control over the transition, but must migrate to Microsoft Graph before April 2027. The service, which was built almost 20 years ago, no longer meets today’s requirements.
Microsoft announced in 2018 that Exchange Web Services would no longer receive functionality updates. In 2023, it announced that EWS would be completely disabled in Exchange Online in October 2026. Now, the company is providing more details about exactly how that process will unfold.
The phase-out will take place in stages and give administrators control over the process. Starting in October 2026, EWS will be blocked by default for tenants who have not explicitly indicated that they still want to use the service. A year later, on April 1, 2027, EWS will disappear from Exchange Online for good. By that time, all organizations must have switched to Microsoft Graph.
Why is EWS being discontinued?
EWS was developed almost 20 years ago and served the ecosystem well, but it no longer meets current requirements in terms of security, scalability, and reliability. Microsoft Graph can now provide functionality comparable to EWS in the vast majority of scenarios.
Microsoft’s own applications have already largely migrated from EWS or are nearing completion. Many third parties have already made the switch or are actively working on it. By removing EWS, Microsoft can reduce its legacy infrastructure, simplify platform behavior, and deliver a more consistent, modern experience.
How does the shutdown work?
Microsoft is disabling EWS per tenant via the EWSEnabled property, which supports three values: True, False, and Null (currently the default). In early 2026, a new feature will be introduced that allows administrators to define an AppID Allow List. When enabled, only apps on that list will have access to EWS.
As of October 1, 2026, the EWSEnabled value for tenants that still have it set to Null will automatically change to False. This means that EWS will be blocked for all applications in that tenant. Organizations that still need EWS will have two options: set EWSEnabled to True and maintain an Allow List, or set EWSEnabled back to Null to continue using EWS without restrictions until its final discontinuation.
Administrators who proactively configure an Allow List and set EWSEnabled to True before the end of August 2026 will be excluded from the automatic change on October 1. Microsoft will pre-populate the Allow List for customers who have not created one before September 2026, based on actual usage per tenant.
Important dates for administrators
The preparation phase has already begun. EWS will remain available, but administrators are advised to take action now. They can view usage reports in the Microsoft 365 admin center and use any published scripts for more information. Optionally, they can populate their Allow List and set EWSEnabled to True before the end of August 2026.
Starting October 1, 2026, EWS will be disabled by default in tenants that have not explicitly chosen to keep it enabled. Administrators can temporarily re-enable EWS if critical workflows are affected, but this will cause an interruption. At the beginning of April 2027, EWS will be permanently removed, and tenant administrators will no longer be able to customize the feature.