Will OAuth 2 be supported for POP3 before the Microsoft October 2020 deadline to require it with Office 365.
We'll add AUTH XOAUTH2 to Pop3 class in the next release, the code is already there and tested.
OAuth 2.0 is available for IMAP for many years.
[Edit] OAuth2 for Pop3 was added.
Mail.dll supports OAuth 2.0 for Imap, Smtp and Pop3:
https://www.limilabs.com/blog/oauth2-office365-exchange-imap-pop3-smtp
https://www.limilabs.com/blog/oauth2-password-grant-office365-exchange-imap-pop3-smtp