In October 2017, we initially published a blog notifying our developer community of our plan to deprecate Outlook REST API v1.0. On November 2020, we announced that we would begin to decommission the Outlook REST API v1.0 endpoint starting from April 30, 2021.

However, due to the pandemic and the effect it has had on our, as well as our partner’s, priorities and work patterns, we will begin the decommissioning of the Outlook REST API v1.0 endpoint starting October 15, 2021.

After this date, applications can no longer call the Outlook Rest API v1.0. If your applications are currently using Outlook REST API v1.0, you should plan to transition to Microsoft Graph to ensure continued access to Exchange Online data.

Thanks for continuing with us on our journey as we work to improve productivity for everyone on the planet.  Please let us know if you have any additional questions or concerns by reaching out to our Q&A Mail forum.

“Testing new features for your apps using beta APIs like this one on the Microsoft Graph API? Help us shape its future.  The Microsoft Graph CPx team runs a Fellowship of the Graph TAP (Technology Adoption Program). This group is a combination of Microsoft Valuable Professionals (MVPs), Regional Directors (RDs), and Independent Software Vendors (ISVs) actively working with Microsoft Graph. If you want to be part of the TAP and receive notifications around changes like this, please complete the TAP submission form for consideration.”