What is happening? Microsoft is ending support for Exchange Web Services (EWS) in Microsoft 365 and Exchange Online. This will result in third-party applications that use EWS to relay and manage email, such as Thunderbird and Aqua Mail, to stop working.
When is this happening? Beginning October 2026.
What is the impact? Those using a third-party tool will need to move to a supported email client such as Outlook for email. See Microsoft 365 email configuration guides for assistance. Note, third-party vendors may make changes or release updates to their applications prior to October 2026 that may affect compatibility with M365. Responsibility for the use of a third-party email application belongs to the individual.
To learn more:
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Deprecation of Exchange Web Services in Exchange Online | Microsoft Learn
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Identify applications using Exchange Online OutlookRESTv2 or Exchange Web Services (EWS) APIs
Questions or concerns? Please contact your IST Account Rep or submit via the IST Help Portal.