Tag: NAA

A February 2025 deadline looms for Outlook classic add-ins that use legacy Exchange tokens for authentication. Add-ins must switch to nested app authentication (NAA) to have continued access to Exchange mailboxes and other objects. The upgrade is easy enough if the ISV that developed the original add-in is still in business. Things get a lot more complicated when they’re not, or you have no idea who developed an add-in.

On April 9, 2024, Microsoft announced a big change in authentication for Outlook add-ins. It’s likely that people don’t realize the kind of change that’s coming. The change removes legacy Exchange authentication methods and replaces them with Nested App Authentication (NAA). Time is running short for developers to upgrade and test their code and Microsoft 365 tenants to get ready for the changeover.