Back in November 2020, Microsoft announced that it deprecates the Outlook REST API Beta and Outlook REST API v2.0 endpoints. This would be a two-year process under Microsoft’s regular services deprecation policy. However, after the end of this two-year period, Microsoft just announced that it delays this depreciation indefinitely.
Microsoft cited customer and partner feedback as reasons for its decision. Apparently, API users aren’t ready to completely ditch it and switch to Microsoft Graph. This would require somewhat major changes to current applications and use cases.
That said, Microsoft cautioned customers not to get too comfortable with the delay or think it’s a long-term option. Although the writedown has been delayed indefinitely, the Redmond tech giant stressed that it will still happen in 2023 and customers will be given six months’ notice before the deadline.
For those unaware, the Outlook REST API is used by developers in applications that manage mailbox data, calendar, contacts, push notifications, and more. However, Microsoft considers it a legacy surface since 2020 and has been encourage customers to migrate to Microsoft Graph using the guide here.
Once the Outlook REST API is inevitably deprecated, developers will no longer have access to the endpoint and the creation of new applications based on the API will be disabled. It remains to be seen when the deprecation date will be next year and what kind of impact it would have on current use cases and scenarios.