Microsoft has announced that it will retire its Exchange Web Services (EWS) API in October 2026.

EWS is a cross-platform API that allows developers to create applications that can access and manage mailbox items in Exchange Online, Office 365, and on-premises versions of Exchange.

“Today, we are announcing that on October 1, 2026, we will start blocking EWS requests from non-Microsoft apps to Exchange Online,” the Exchange Team said on Tuesday.

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“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.”

Microsoft has stated that it is retiring EWS in order to focus on its newer and more modern API, Microsoft Graph. Microsoft Graph provides a unified API for accessing data across Microsoft 365, including Exchange, SharePoint, and Teams.

Microsoft has encouraged EWS developers to start migrating their applications to Microsoft Graph as soon as possible. The company has provided a number of resources to help developers with the migration process, including a migration guide and a set of sample codes.

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