The other serious omission is the ability to have a different SMTP server for sending emails. Don't mind the OAUTH2 for connecting to read emails but to not be able to specify a different outgoing server under the assumption that the same server will be used is not ok. We use aliases and we do not want/need a meaningless alphanumeric string followed by "on behalf of" and then the email address - this is avoided by using your own SMTP server. This still can all be achieved with a good level of security, but to remove the flexibility is short sighted. Considering we pay Microsoft too, handsomely, for the service (not simply "free" outlook.com customers), and we were lied to by Microsoft support before 16th Sept who promised suitable "app updates" to allow this flexibility which unsurprisingly never materialised, we are far from happy. Being forced to do the "Microsoft thing", the "Microsoft way" - only use their apps in the way they want is not ok, not the only answer, and not the only way to comply/migrate to modern security requirements, which no-one should have an argument against, if implemented in a more thoughtful way.