If you are referring to Basic Auth in Exchange Online:
https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-and-exchange-online-february-2021-update/ba-p/2111904
The first change is that until further notice, we will not be disabling Basic Auth for any protocols that your tenant is using. When we resume this program, we will provide a minimum of twelve months notice before we block the use of Basic Auth on any protocol being used in your tenant.
We will continue with our plan to disable Basic Auth for protocols that your tenant is not using. Many customers don’t know that unneeded legacy protocols remain enabled in their tenant (Security Defaults takes care of this for newly created tenants now). We plan to disable Basic Auth for these unused protocols to prevent potential mis-use. We will do this based on examining recorded usage of these protocols by your tenant, and we will send Message Center posts providing 30 days notice of the change to your tenant. This work will begin in a few months.