M365 Changelog: Retirement of Exchange Web Services in Exchange Online

MC676299 – In 2018, Microsoft announced that it was no longer making feature updates to Exchange Web Services (EWS) in Exchange Online, and it advised developers to move to Microsoft Graph.

Today, Microsoft is announcing that on October 1, 2026, Microsoft will start blocking EWS requests from non-Microsoft apps to Exchange Online.

When this will happen:

October 1, 2026

How this affects your organization:

While the EWS components of the service will continue to receive security updates and certain non-security updates, product design and features will remain unchanged. This change also applies to the EWS SDKs for Java and .NET, as well.

Despite this announcement, EWS is still available and supported for use in production environments. But Microsoft strongly suggests migrating to Microsoft Graph to access Exchange Online data and gain access to the latest features and functionality.

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.

Migrating Applications to Microsoft Graph

Microsoft knows there are several feature gaps between EWS and Microsoft Graph, and though the list below is not exhaustive, these are the gaps most frequently reported to us by developers:

  • Access to Archive Mailboxes – Microsoft is working on delivering access to archive mailboxes via Microsoft Graph and will provide an updated timeline in the coming months.
  • Folder Associated Information / User Configuration – Microsoft is working on these features and will provide an updated timeline in the coming months.
  • Exchange Online Management – Microsoft is investigating solutions for this and will provide an updated timeline in the coming months.
  • Access to Public Folders – Microsoft is reviewing the need to provide third-party app access to Exchange Online public folders via the Graph API and are interested in hearing from customers and partners who build solutions that use public folders, other than backup and restore solutions. If you are willing to share details on how you use EWS with public folders, we’d love to hear from you, and you can reach us at [email protected]

Microsoft knows there are other gaps not listed above, and it continues to work on closing them, but it’s possible some functionality will not make it to Microsoft Graph. Microsoft encourages you to provide feedback to us, keep a close eye on the What’s new in Microsoft Graph page, and explore alternatives for functionality or features not available in Microsoft Graph.

Next Steps

The retirement of these APIs follows our Modern Lifecycle Policy. Microsoft understands changes like this may cause some inconvenience, but Microsoft is confident it will ensure more secure, reliable, and performant experiences.

Microsoft will publish regular communications as it progresses toward this deadline to aid affected tenants in identifying EWS usage. Microsoft encourages all customers to monitor Message Center and this blog for related content.

Thank you in advance for updating and opening your apps to a wider range of useful and intelligent features on Microsoft Graph. Microsoft is extremely excited about the growing opportunities that Microsoft Graph offers to developers, and it remains fully committed to our journey to empower developers to access Microsoft 365 data with the most modern features and tools.