This message is a follow-up to our earlier communication regarding the deprecation of Discovery Service API.
The Discovery Service API was used with earlier versions of Office service APIs for discovering Calendar, Contacts, Mail, MyFiles (for OneDrive and OneDrive for Business service endpoints), Notes (for OneNote), and RootSite (for SharePoint). The release of Microsoft Graph REST APIs allowed developers to integrate with Microsoft 365 services in a simplified way. Because there was no need for the Discovery Service API, the access to the API was limited to applications already using the API. Developers have since been migrating away from using the Discovery Service API to use the unified endpoint offered through Microsoft Graph REST APIs.
If you are still using the Discovery Service API to locate the service endpoint, please note that beginning November 1, 2019, API requests to the Office 365 Discovery Service endpoint api.office.com/discovery will no longer work.
What do I need to do to prepare for this change?
If you are still using the Discovery Service API, please update your code to use the Microsoft Graph API, which allows integration with productivity services such as Calendar, Files, Mail, and so on. For more details, see the Microsoft Graph documentation.
Sudhi Ramamurthy <email@example.com>