Microsoft revealed some interesting Exchange Online statistics at the MEC 2022 event. 300 K physical mailbox servers is a staggering amount, but 7.3 billion mailboxes might be even more surprising. Also at MEC we discovered more about the campaign to remove basic authentication from Exchange Online and how well Microsoft’s Greg Taylor can communicate in Irish when he presents about the deprecation of basic authentication.
The Microsoft 365 admin center includes the ability to manage settings for the default Exchange Online authentication policy. You might have other policies to allow selective access with basic authentication to some protocols; these policies must be managed with PowerShell. Authentication policies are part of the journey to eliminate basic authentication from Exchange Online, now expected to happen in mid-2021.