Exchange Online Shutdowns Through 2023

Service shutdowns and software support terminations are coming to Exchange Online through the end of 2023. The most notable events are shown on the accompanying timeline. Customers should verify that they are not affected or have plans to move to supported services and software.

Basic Authentication

In Oct. 2022, Exchange Online will begin to randomly select tenants and shut down Basic Authentication in those tenants for protocols other than Simple Mail Transfer Protocol (SMTP). Tenants will be able to opt out of the change temporarily, but Microsoft says that Basic Authentication will be gone for all tenants, with no opt-out, after the first week of Jan. 2023. Replacing Basic Authentication with so-called Modern Authentication (OAuth 2.0) will enhance security against brute force attacks on passwords, but it will break some third-party clients and add-on services. Exchange Online is enabling Modern Authentication for some legacy protocols, including Exchange ActiveSync, IMAP, and POP, which will resolve some compatibility problems. However, customers may need to upgrade each client and take other steps to take advantage of Modern Authentication. Organizations can use Azure Active Directory (AAD) sign-in logs to locate clients using Basic Authentication and target them for upgrades.