M365 Changelog: Upcoming API Retirements in Exchange Web Services for Exchange Online

MC296195 – Updated March 04, 2022: Microsoft has updated the content below for clarity.

Today Microsoft is announcing the retirement of support for the 25 least used APIs of EWS for Exchange Online (as determined by the call volume into the service).

Microsoft is retiring support for these APIs as Microsoft begins the process of reducing the surface area of the EWS protocol for maintenance and security purposes. 

In the coming months Microsoft will send Message Center posts to tenants it can see are using these low volume APIs.

Over the last few years, Microsoft has invested heavily in Microsoft Graph to enable developers to access the rich data available in Microsoft 365. Microsoft Graph, along with OAuth 2.0, provides increased security and seamless integration with other Microsoft cloud services.

Key points

  • Timing: Late March, 2022
  • Action: Microsoft strongly urges you and our ecosystem partners that access Exchange Online data to migrate to Microsoft Graph APIs.

How this will affect your organization:

These APIs will no longer be supported and Microsoft will introduce sunset headers in the response for these APIs that are marked for retirement. These APIs will continue to function until they are fully retired, in the future, but will no longer be supported or updated.

Note: Retirement of support for these APIs is the first in a series of steps Microsoft will take as it sunsets EWS for Exchange Online. Over time, Microsoft will identify additional APIs for retirement when and where it sees adequate parity with Microsoft Graph APIs.

The list of APIs that will be retired is available here.

Learn more: