Service Update
| Availability | February 13th, 2025 |
| Product(s) | Mimecast Essential for Outlook (MEO) |
| Who's affected | Mimecast Essential for Outlook (MEO), Administrators |
Microsoft has announced the deprecation of Exchange user identity tokens, effective February 17th, 2025. This deprecation impacts Mimecast Essentials for Outlook, specifically when the Enable JSON Web Token Authentication option is enabled within Authentication Profiles. Mimecast is actively working with Microsoft to support the new Nested App Authentication, though this functionality is not available yet. Updates regarding availability will be communicated as they become available.
The recommended action below allows administrators to enable Legacy Exchange Online tokens so that Mimecast Essentials for Outlook can continue to use JSON Web Token Authentication.
Recommended actions
- Review your Authentication Profiles to check if you are using JSON Web Token Authentication by:
- Navigate to Services | Applications | Authentication Profiles.
- Review your existing profiles to determine if Enable JSON Web Token Authentication (Mimecast Essentials for Outlook only) is enabled.
- If you are using JSON Web Token Authentication, follow Microsoft's advice to re-enable Exchange Identity Tokens.
- Ensure this is performed prior to February 17th, 2025.
Comments
Are we to expect an update to the MEO plug-in in the near future? Just wondering if it is worth performing the work-around if something better is being produced?
Thank you for your feedback.
We recommend that you implement the workaround.
Per Microsoft even after re-enabling these tokens the change in June will force them off again will there be an update to the addon to use Nested App Authentication befor then?
Thank you for your feedback. Please note that further updates regarding the authentication changes will be provided.
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