Sigh... this is why implementing IMAP is a beast... Also doesn't cover what Exchange/Office 365 adds to the mix.
I'm happy to see a newer standard that is at least simpler to understand and implement.
Unfortunately Exchange adds almost nothing to the mix, they support only a bare minimum of imap extensions (only literal+ if i remember correctly) and much stuff is not supported
https://developers.google.com/gmail/imap/imap-extensions