Microsoft is set to enhance the security of Outlook add-ins by phasing out legacy Exchange Online tokens and introducing a modern approach called Nested App Authentication (NAA). This shift not only bolsters security but also streamlines authentication, offering a seamless single sign-on (SSO) experience for applications embedded within Microsoft apps like Outlook.
If your organization relies on legacy tokens, it’s crucial to act now to ensure compliance and uninterrupted functionality.
What Is Changing?
Legacy Exchange Online tokens, used to authenticate Outlook add-ins, are being replaced by the more secure Nested App Authentication. NAA enables a more robust integration, aligning with Microsoft's focus on security and user convenience.
Key Dates for Deprecation:
- February 2025: Legacy tokens will be disabled by default. Administrators will have the ability to reenable them temporarily using PowerShell.
- June 2025: The option to reenable legacy tokens will be removed. Administrators must contact Microsoft for exceptions.
- October 2025: Legacy tokens will be permanently disabled for all tenants with no exceptions.
Learn more about these changes on Microsoft's official FAQ page.
Why Migrate to Nested App Authentication?
- Enhanced Security: NAA eliminates vulnerabilities associated with legacy tokens by using modern, token-based authentication mechanisms.
- Seamless SSO: Offers users a better experience by enabling single sign-on functionality across embedded applications.
- Future-Proofing: Migrating ensures your add-ins remain operational after October 2025, avoiding disruptions.
Steps to Prepare for the Transition
For Developers
- Identify Affected Add-ins: Check if your Outlook add-ins rely on legacy Exchange tokens.
- Migrate to NAA: Update your add-ins to support Nested App Authentication.
- Test Thoroughly: After migrating, test the add-ins to confirm they function as expected without legacy tokens.
For Administrators
- Audit Add-ins: Identify and list all Outlook add-ins that utilize legacy tokens.
- Coordinate with Developers: Work closely with your IT or vendor teams to ensure they migrate add-ins before deadlines.
- Manage Legacy Tokens: Use PowerShell commands to temporarily reenable legacy tokens during the transition period if required.
Follow these steps outlined by Microsoft to manage Exchange tokens.
Impact of Missing Deadlines
Failure to transition to Nested App Authentication by October 2025 will result in Outlook add-ins losing functionality. Organizations that delay this migration may face disruptions, increased security risks, and compliance issues.
Take Action Today
The deprecation of legacy tokens and introduction of Nested App Authentication represents a significant step forward in enhancing security for Outlook users. By proactively adopting NAA, developers and administrators can ensure smooth transitions while staying ahead of security compliance.
For more detailed information, refer to Microsoft’s official updates:
Stay ahead of these changes to keep your Outlook environment secure and efficient!
