What happens if we do not migrate from EWS before April 2027?

After April 1, 2027, EWS will be permanently disabled in Exchange Online, so applications that still depend on EWS will no longer be able to use it to access Exchange Online data. Organizations could experience failures in email, calendar, synchronization, notifications, or other business processes that rely on those connections. This makes it important to identify and address EWS dependencies well before the final shutdown.

When is the Microsoft EWS retirement deadline?

Microsoft will begin disabling EWS for Exchange Online tenants on October 1, 2026, as part of a phased rollout. The final and permanent shutdown is scheduled for April 1, 2027. Organizations should therefore treat October 2026 as a critical preparation milestone rather than waiting for the final 2027 deadline.

How do I find applications that are still using EWS?

Organizations can use Microsoft’s EWS Usage Reports and EWS Analyzer to identify applications, users, actions, and activity associated with EWS. IT teams should then work with application owners and vendors to understand what each dependency supports and how critical it is to the business. This assessment helps organizations prioritize which workloads need immediate attention and which can follow a longer migration path.

How do I migrate from EWS to Microsoft Graph?

The migration approach depends on how an application currently uses EWS and which Exchange Online capabilities it requires. Microsoft provides EWS-to-Graph API mappings and other migration resources to help organizations identify equivalent Graph capabilities, while some scenarios may require application redesign or an alternative solution. Organizations should assess, develop, test, and validate each workload before moving it into production rather than treating the transition as a simple API replacement.

Can EWS Allow Lists extend the Microsoft EWS retirement deadline?

EWS Allow Lists can help organizations maintain access for approved applications during the phased retirement, giving IT teams additional time to complete migration work. However, they are a temporary measure and do not extend the final April 1, 2027 EWS shutdown. Organizations should use the additional time to complete their migration rather than rely on the Allow List as a long-term solution.