M365 Changelog: (Updated) Basic Authentication Deprecation in Exchange Online – May 2022 Update
MC375736 – Updated May 10, 2022: Microsoft has updated this post to show as intended. Thank you for your patience.
In about 150 days from today, Microsoft is going to start to turn off Basic Auth for specific protocols in Exchange Online for those customers still using it.
Timeline and Scope
As Microsoft communicated last year in blog posts and MC286990, it will start to turn off Basic Authentication in its worldwide multi-tenant service on October 1, 2022. To clarify, Microsoft will start on October 1; this is not the date it turns it off for everyone. The company will randomly select tenants, send 7-day warning Message Center posts (and post Service Health Dashboard notices), then it will turn off Basic Auth in the tenant. Microsoft expects to complete this by the end of this year. You should therefore be ready by October 1.
Microsoft is turning off Basic Auth for the following protocols: MAPI, RPC, Offline Address Book (OAB), Exchange Web Services (EWS), POP, IMAP, Exchange ActiveSync (EAS) and Remote PowerShell.
Microsoft is not turning off SMTP AUTH. Microsoft has turned off SMTP AUTH for millions of tenants not using it, but if SMTP AUTH is enabled in your tenant, it’s because the firm sees usage and so it won’t touch it. Microsoft does recommend you disable it at the tenant level and re-enable it only for those user accounts that still need it.
Exceptions and Per-Tenant Timing
There is no way to request an exception after October. Tenant selection is random, and Microsoft cannot put your tenant to the back of the queue to give you more time or change your settings on any specific date. If you want Basic Auth to be disabled at a time of your choosing (either now, or as soon as you are ready), use Authentication Policies.
What should I do to prepare for this change?
Any client (user app, script, integration, etc.) using Basic Auth for one of the affected protocols will be unable to connect. The app will receive an HTTP 401 error: bad username or password.
Any app using Modern Auth for these same protocols will be unaffected.
To read more on what can be done to switch apps from Basic to Modern auth please view Microsoft’s main documentation page and the latest blog.