> Will VPO3 be including support for OAuth2 authentication in a future version please?
> This will shortly become mandatory for using Gmail with POP3/SMTP.
> I suspect also it is, or will become necessary for Hotmail/Outlook.com accounts too, so not just limited to Gmail
We are investigating it, but it is not currently a high priority, because Gmail, Hotmail, Outlook.com, etc are generally not the sort of email accounts that will be used with VPOP3, because they are all designed for individual users, rather than a whole business, so the requirement to work with these accounts is an edge-case.
A big problem is that OAuth2 is not designed for unattended access, so Oath2 access tokens typically have a limited lifespan. When that lifespan is up, then the user needs to reauthenticate with the server, and that is an interactive process, so VPOP3 would not be able to do it automatically. Essentially, at some point, VPOP3 would be unable to collect or send mail until an administrator logs into the server and reauthenticates. This could cause severe disruption for the business. The authentication process is also not designed to be done 'remotely'. Usually it will be done on the same computer or device that the email client is running on, which would be the VPOP3 computer itself in this case (not via the VPOP3 administration console). The authentication & reauthentication processes involve the user actually viewing (for example) Google's website, and entering their authentication details into a form there, as well as, possibly, using two-factor authentication on Google's website. This could not be automated.