Upcoming API Changes: Transitioning to Microsoft Graph for Hybrid and Cloud Environments

Starting February 2025, Microsoft will deprecate Exchange Web Services (EWS) and REST API for tenants using Azure O365 or hybrid setups. This change applies to both new and existing customers. Note that new Microsoft 365 tenants already have these APIs deactivated by default. 

To avoid service interruptions, customers must transition to the Microsoft Graph API, which provides enhanced security and an improved user experience, particularly for mobile users. 

Important note 

Microsoft offers an option to temporarily opt-in to legacy authentication methods, extending EWS and REST API functionality until June 2025. However, this approach is highly discouraged due to its security vulnerabilities. We strongly recommend transitioning to Microsoft Graph API as soon as possible for improved security and performance. 

Benefits of transitioning to Microsoft Graph API 

1. Enhanced login experience for mobile users: Mobile users gain seamless access without requiring a second login. 

2. Improved security: Customers can leverage Conditional Access policies to: 

   • Require Multi-Factor Authentication (MFA) 

   • Block access from specific regions 

   • Restrict access from unverified devices 

Action required by environment 

1. On-Premise instances: 

   • Impact: No changes required. EWS and REST API will remain functional. 

   • Next Steps: None. 

2. Hybrid setups: 

   • Impact: EWS and REST API will stop functioning in January 2025. 

   • Next Steps: 

     • Migrate to the Microsoft Graph API. 

     • For hybrid environments with users split between On-Premise and Azure, create separate PRB configurations and deploy them individually. 

       • Note: This may affect how reports are consolidated. 

     • For unsupported hybrid setups (e.g., separate On-Premise and Azure instances), migrate PRB to the On-Premise instance. 

3. Cloud Tenants: 

   • Impact: EWS and REST API will stop functioning in January 2025. 

   • Next Steps: Migrate to the Microsoft Graph API. No additional configuration is required, as all PRB clients already support Graph API. 

Who needs to take action? 

Customers using hybrid or cloud-only email systems need to migrate to Microsoft Graph API. If you’re unsure about your environment, consult your IT team. 

How do I migrate?

You can find more information here: Button migration from REST API to Graph API

External Resources 

For more details on the transition, refer to the following resources: 

• Microsoft Tech Community: Retirement of Exchange Web Services 

• Upcoming Changes to Exchange Web Services API 

• Outlook REST API Decommissioning Update 

• Nested app authentication and Outlook legacy tokens deprecation FAQ 

• Turn legacy Exchange Online tokens on or off 

For any questions or additional support, please contact our Customer Success team.