Basic Authentication Deprecation in Exchange Online – September 2022 Update

LoopEndle The ticket that you had opened is closed; please refer to this blog post (and your tenant's Message Center posts) for the latest status on basic auth retirement.

Note that we have announced plans to retire basic authentication in Exchange Online just about 3 years ago. The last extension for basic auth use with Exchange Online that we have for our customers is until January 2023 (see details in your tenant Message Center).

albertfont As this very blog post says:

We will not be disabling or changing any settings for SMTP AUTH.

The statement can also be found in this documentation: 

SMTP AUTH will still be available when Basic authentication is permanently disabled on October 1, 2022. The reason SMTP will still be available is that many multi-function devices such as printers and scanners can't be updated to use modern authentication. However, we strongly encourage customers to move away from using Basic authentication with SMTP AUTH when possible. Other options for sending authenticated mail include using alternative protocols, such as the Microsoft Graph API.

For information on how to enable SMTP Auth for specific mailboxes, please see this document.