Understanding Modern vs. Legacy Authentication in Microsoft 365
Since October 2019, Microsoft has enabled Security Defaults by default in new Microsoft 365 tenants. Security Defaults are a group of best-practice security settings, and one of note is the disablement of all legacy authentication, which itself has been off in Exchange Online and SharePoint Online, by default, since August 2017. The term legacy authentication doesn't refer to one particular protocol, but rather any that do not support Multi-Factor Authentication (MFA). Protocols that support…