Exchange Online Discontinues Support for Basic Authentication
Via the message portal in the Office365 Admin Center, Microsoft has again pointed out that as of October 13, 2020, basic authentication for EWS, EAS, IMAP, POP and RPS will no longer be offered for accessing Exchange Online. Client applications that using Basic Authentication for EWS will no longer be able to connect to Exchange Online at that time. This change does not affect SMTP authentication and applications using OAuth 2.0 will continue to work with these protocols without modification or interruption.
Microsoft recommends that all Office365 subscribers get started as soon as possible to migrate or replace e-mail applications that still use basic authentication. For this purpose, AzureAD offers an extended report that is designed to help companies identify the users and applications affected.
Source: Microsoft