Heads Up: Microsoft Graph API Updates Affecting Sensitive Email Properties

Introduction: Critical Changes to the Graph API

Hello everyone,

If you're developing applications that interact with the Microsoft Graph API, especially those dealing with email, there's an important change coming that you need to be aware of. Starting December 31, 2026, Microsoft will be restricting updates to sensitive properties on non-draft email messages (those already sent or ready to be sent). This means updating the subject, body, or recipients will require additional permissions. This change will particularly affect applications used in enterprise environments.

In this article, we'll break down what this change means for you, how it might impact your applications, and, most importantly, how to prepare.

Scope of the Change: Which Properties Are Affected?

According to Microsoft's announcement, the following properties will be affected by this change:

• Subject: The email's title.
• Body: The email's content.
• Recipients: The email's recipients (To, CC, BCC).

Updating these properties after December 31, 2026, will require the Mail.AdvancedReadWrite permission or broader permissions like .All / .Shared, along with administrator consent. Your application will need these permissions granted by an administrator to continue modifying these fields.

Why Is This Change Happening?

Microsoft states that the primary reason for this change is to enhance security and data integrity. The goal is to prevent unauthorized or malicious modification of sensitive email properties, providing an extra layer of protection against phishing attacks and other cybersecurity threats.

Impact and Action Steps for Developers

So, what does this change mean for you as a developer working with the Microsoft Graph API? Here are key considerations and steps you should take:

1. Review Existing Applications: Identify all applications that use the Microsoft Graph API to interact with email, especially those that update the subject, body, or recipients. Check which permissions these applications currently have and whether they have administrator consent.
2. Request Necessary Permissions: If your applications need to update the affected properties, request the Mail.AdvancedReadWrite permission or the broader permissions (.All / .Shared). Remember that these permissions require administrator consent.
3. Obtain Administrator Consent: After requesting the permissions, have your organization's Microsoft 365 administrator approve them. Without administrator consent, your application will not be able to access these properties after December 31, 2026.
4. Test in a Test Environment: After obtaining the permissions, run your application in a test environment to ensure that everything works as expected. Verify that email update operations are performed smoothly.
5. Inform Users: If you need to make changes to your application, inform your users about these changes so they are prepared.

Example Scenario: CRM Integration

Let's say your organization uses a CRM (Customer Relationship Management) system that tracks and updates emails via the Microsoft Graph API. For example, after a meeting with a customer, the CRM system automatically updates the email subject or body to add information to the corresponding customer record. In this case, the CRM system needs to have the necessary permissions and administrator consent to continue working after December 31, 2026.

Technical Details: How to Request and Manage Permissions

There are different ways to request and manage permissions in the Microsoft Graph API. Here are some common methods:

• Azure Active Directory (Azure AD) Portal: You can view your applications' permissions, request new permissions, and provide administrator consent through the Azure AD portal.
• Microsoft Graph PowerShell: You can also manage permissions using PowerShell. For example, you can use the Get-MgServicePrincipal command to view an application's existing permissions and the Update-MgServicePrincipal command to add new permissions.
• Microsoft Graph API: You can also manage permissions by making direct API calls. For example, you can update an application's permissions via the /applications/{id} endpoint.

Whichever method you use, ensure that the permissions are configured correctly and that administrator consent is obtained.

Best Practices and Recommendations

Here are some best practices and recommendations to consider as you prepare for these changes:

• Be Proactive: Don't wait for the changes to take effect. Take the necessary steps now to ensure that your application continues to work smoothly.
• Use a Test Environment: Always test permission changes in a test environment before applying them to the live environment. This will help you identify and resolve potential problems in advance.
• Review Documentation: Regularly review the official documentation published by Microsoft. This will ensure you have the most up-to-date information about the changes.
• Review Security Policies: This change may be a good opportunity to review your company's security policies. Consider taking stricter measures, especially regarding email security.

Conclusion: Being Prepared Is Key to Success

This change in the Microsoft Graph API can have a significant impact on applications that interact with email. However, by taking the right steps and being prepared, you can overcome this situation. As Fiboo, we are ready to provide our customers with the support they need to succeed in this process.

Remember, being proactive and taking the necessary precautions will ensure that your application continues to work smoothly after December 31, 2026.

Best regards!