Hi @delaynomore ,
Welcome to our forum, please kindly understand that here we mainly focus on general issue about Outlook desktop client.
For your issue, I have researched a lot but haven't found the specific article mentioned it. I just found this article, which mentioned "we have decided to postpone disabling Basic Authentication in Exchange Online for those tenants still actively using it until the second half of 2021." For more detailed information, you could refer to the article above.
Hope that would be helpful to you.
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