MC296195 – Today Microsoft is announcing the deprecation of the 25 least used APIs of EWS for Exchange Online (as determined by the call volume into the service).
Microsoft is retiring these APIs to begin the process of reducing the surface area of the EWS protocol for maintenance and security purposes. After the retirement, support will end for these APIs.
In the coming months Microsoft will send Message Center posts to tenants they can see are using these low volume, and now deprecated APIs.
Microsoft will also remove the ability to register new apps in Azure with EWS permissions starting September 30, 2022. Apps registered before this date, any API not mentioned in this, or subsequent announcements, will not be impacted.
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.
How this will affect your organization:
Microsoft will introduce sunset headers in the response for these APIs that are marked for retirement. As per Microsoft’s retirement policy, they will decommission these APIs by March 31, 2022.
Note: This set of retirement is the first in a series of steps Microsoft will take as they sunset EWS for Exchange Online. Over time, Microsoft will identify additional APIs for deprecation when and where they see adequate parity with Microsoft Graph APIs.
The list of APIs that will be retired is available here.