Microsoft has published the official timeline for retiring Exchange Web Services (EWS) in Exchange Online. For many years, EWS served as a core protocol for integrating third-party applications, migration tools, and hybrid coexistence scenarios. The future, however, lies with the Microsoft Graph API, which provides modern security capabilities and more advanced functionality. The deprecation of EWS is part of Microsoft’s broader initiative to strengthen cloud security and unify its API landscape.
After this date, access to Exchange Online data will only be possible through the Microsoft Graph API (sources: learn.microsoft.com, neowin.net, thecyberexpress.com, mc.merill.net).
The impact is especially relevant for organizations operating hybrid environments (Exchange On-Premises + Exchange Online). Many rich coexistence features - such as Free/Busy lookups, MailTips, and profile photo synchronization – still rely on EWS through a Shared Service Principal. This principal was retired in October 2025.
Microsoft now requires organizations to adopt a dedicated hybrid application in Entra ID and transition to Graph-based authentication. Failure to implement these changes will result in functional disruptions, particularly in hybrid calendar integration (thecyberexpress.com, community....ection.com).
The retirement of EWS marks a significant shift toward improved cloud security and platform modernization. Organizations should use the remaining time to adapt their systems and processes. Those who transition early to Microsoft Graph not only avoid service disruptions but also benefit from enhanced security, expanded capabilities, and a future-ready API foundation.
Whether you need clarification or hands-on support, feel free to contact us. We’re here to guide you through the transition.
Whether you need clarification or hands-on support, feel free to contact us. We’re here to guide you through the transition.
