The End of EWS Is Approaching

The retirement has been anticipated since 2018, when Microsoft announced it would no longer update EWS features. While the technology will remain available after the cutoff date, it will no longer be maintained. EWS requests to Exchange Online and Microsoft 365 will be blocked. EWS in Exchange Server (on-premises) is not affected. Developers must switch to using Microsoft Graph, although it currently lacks some features. 

Public Folders Limited to Outlook Clients

Microsoft recently commented on access to public folders: Based on usage data, programmatic access to public folders will be limited to supported Outlook clients and for bulk import/export purposes only. APIs for creating, reading, updating, and deleting public folders will no longer be available (see also security-related updates in Exchange Online).

Other EWS functionalities are also not yet available in Microsoft Graph. Microsoft is working on filling these gaps by the deadline. Still, now is the right time to begin the migration. A list of apps and background services using EWS can be found in the Microsoft 365 Admin Center under «Usage/Reports.» These should be transitioned to Graph as soon as possible. Incompatible applications should be replaced promptly. As an interim solution, mailboxes can be moved to an on-premise server.