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TonyRedmond's avatar
TonyRedmond
MVP
Apr 29, 2025

How to Find Active EWS-Based Apps in a Microsoft 365 Tenant

Microsoft will retire Exchange Web Services (EWS) from Exchange Online on October 1, 2026. A new usage report helps tenants understand what apps use EWS. Many of the apps are likely to be first-party...
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TonyRedmond's avatar
TonyRedmond
MVP
May 09, 2025

Try searching Google or Bing to find any references to the GUID you see. If you can’t find anything, the app is likely an internal Microsoft app.

  • ArjanBroekhuizen's avatar
    ArjanBroekhuizen
    Iron Contributor
    May 13, 2025

    Hi TonyRedmond​ 

    Thanks for replying. I have searched the GUID's with Google, but no results show up. So these would be internal Microsoft apps.

    Some Microsoft apps are still using EWS (for example Microsoft Teams, Microsoft Outlook or Office 365 Exchange Online are on the EWS Usage report). Do we have to take action for these apps? Or can we ignore them and will Microsoft change these apps so these will not use EWS anymore?

    Kind regards,
    Arjan

    • TonyRedmond's avatar
      TonyRedmond
      MVP
      May 13, 2025

      Microsoft will take care of its own apps by October 2024. The ones you've got to worry about are those from ISVs or internally-developed apps.

      • Scootsie2's avatar
        Scootsie2
        Copper Contributor
        Nov 19, 2025

        Hi Tony Redmond​,

         

        Is this confirmed for October of 2024 or 2025? Reason of asking is we have first party apps (we assume) popping up yet on our EWS report. These app ids have no corresponding entry as an internal app or in the Enterprise apps including all results. 

         

        Guessing these are nonfactor for us to worry about, but seeking that confirmation.

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