I see @stanhu's work has previously been done to support OAuth2 for google and has been completed for Microsoft Graph including the use of their API. I'd like to have the same implementation for Google where I could remove the whole "IMAP" stuff and simplify my infrastructure demands through the support of a port 443/https outbound with OAuth2 taking care of authentication. This simplification reduces the demands of security compliance as well as it reduces outbound ports and protocols that have to be justified. GitLab is already using 443 and https. https://developers.google.com/gmail/api