Nested app authentication (NAA) and deprecation of Exchange legacy tokens

Microsoft has launched a new method for Outlook add-in authentication called nested app authentication (NAA). NAA replaces the current authentication method, which Microsoft now refers to as "legacy tokens".

To ensure the Signature 365 add-in continues to work, you have the following options:

• Upgrade the add-in to version 3.0 - preferred option
• Continue using the current add-in version manually granting new required permissions
• Re-enable legacy tokens

Upgrade the add-in to version 3.0

We strongly recommend all customers upgrade the add-in to version 3.0.

This will ensure that you are using the latest version of the add-in, and are able to take advantage of the newest updates and features.

As part of this process you will be asked to grant admin consent to two new permissions ("Maintain access to data you have given it access to" and "Sign in and read user profile"). This does not grant Signature 365 any additional access to data but is required for NAA to work.

Updating the Signature 365 modern add-in: Signature 365 Help Center

**Continue using the current add-in version by manually granting new required permissions**

You must manually grant admin consent to two new permissions ("Maintain access to data you have given it access to" and "Sign in and read user profile"). This does not grant Signature 365 any additional access to data, but it is required for NAA to work.

This process must be performed by a Global Admin or a user with the permission to grant the admin consent required within Microsoft 365.

Complete manual consent for your existing add-in

You can then upgrade to version 3.0 at a point to suit your company.

Re-enable legacy tokens

For customers that cannot perform either of the above options, Microsoft allows legacy tokens to be re-enabled by using PowerShell. Follow the steps in the article below if you want to use this method.

Signature 365 - Enable legacy Exchange Online tokens