[sir]

If you use this proxy of mine then any IMAP (or POP/SMTP) client can be used with a “modern” email provider, regardless of whether it supports OAuth 2.0 natively: https://github.com/simonrob/email-oauth2-proxy. No need for your client to know about OAuth at all.

[tpoacher]

This looks great! Does it work in a way that would make it need to be "authorized" by the organization?

Recently I wanted to use the alpine terminal email client, which does support OAuth2, but I was thwarted by a notice saying "application alpine requesting access; write to your admin to authorise". Several months later, apparently whether to add alpine or not to the list of approved software is still "being discussed". Not exactly holding my breath for it ...

[sir]

You do still need details for an authorised client, but it’s possible to use those of one that’s already approved. See the readme section that explains this aspect: https://github.com/simonrob/email-oauth2-proxy#oauth-20-clie...