Microsoft has been slowly trying to get its Exchange Online users to switch from Exchange Web Services (EWS) for accessing data in favor of Microsoft Graph. In 2018, the company revealed that EWS in Exchange Online would no longer get any feature updates. This week, the company announced a date when it would no longer allow EWS requests from non-Microsoft apps to Exchange Online.
In a blog post, Microsoft stated that those specific EWS requests would be blocked starting on October 1, 2026. That will give Exchange Online users over three years to make the necessary preparations.
Today’s announcement and the retirement of EWS apply only to Microsoft 365 and Exchange Online (all environments); there are no changes to EWS in Exchange Server. Further, the changes in Exchange Online do not affect Outlook for Windows or Mac, Teams, or any other Microsoft product.
Even with this date, Microsoft says that the EWS components of the service will keep getting security updates, along with some unnamed non-security updates. It's also still available and supported in production environments.
Having said that, Microsoft still feels users should make the change to Microsoft Graph in order to get access to their Exchange Online data. The company knows there are some feature gaps that EWS has that Graph currently does not. That includes access to archive mailboxes, Folder Associated Information / User Configuration, and Exchange Online Management. Microsoft is working on all of these for Graph and says it will offer an updated timeline for them "in the coming months."
One other feature that EWS currently has, Access to Public Folders, is currently being evaluated by Microsoft as a Graph feature. It stated it is looking for "details on how you use EWS with public folders" and those comments can be sent to EWSandPFfeedback@microsoft.com.
Microsoft also admits that while they are trying to include as many EWS features in the Graph API as it can, "it’s possible some functionality will not make it to Microsoft Graph."