RE: Microsoft ending the support for Basic Authentication / Service / IMAPS
Hi Georg,
For you information, I have taken up this question with our NPR and according to shared internal roadmaps, it seems that the implementation of OAuth2 for IMAP, POP3 and maybe SMTP is planned during 2020/nov-dec, though it might be pushed over to 2021/jan-feb.
As I understand it, the support for Basic Authentication for SMTP will be prolonged due to its widespread usage, but I suppose that it would be natural to also include OAuth2 support for SMTP as well.
It also seems that they are looking into the Graph API For Exchange/O365 as an alternative, but that part had a question mark, so this cannot be verified. But that would be the logical and probably better alternative for communicating with newer Exchange/O365 for SO onsite.
As SO foremost are advocating the use of SO Online where MailGun is used, this might affect the decision regarding implementing support for the Graph API. I'm not exactly sure about which methods that are used when communicating with MailGun, but I believe that their REST API is used for polling the mail. Normal SMTP-protocol might be used for sending mail though.
I hope this gives you some hints about the upcoming plans. But, best would be if someone from RnD could elaborate a bit on this question.
Best Regards
Marcus