Update: The full timeline for retirement of Basic Authentication in Exchange Online is now published in Basic Authentication Deprecation in Exchange Online – September 2022 Update.
It’s been a few ...
Updated Sep 01, 2022
Version 7.0
Blog Post
> First port of call should be to speak to that vendor and ask what their plans are.
We are one of the affected vendors (http://www.emclient.com). We have been trying to push Microsoft for months to provide us support for this with no success. The issue is that we rely on the Offline AddressBook protocol for providing access to global address book. Outlook for Mac has been using this protocol too but it was not available to 3rd-parties. After numerous attempts to communicate with Microsoft we only got this lousy knowledge base article which is of zero help: https://docs.microsoft.com/en-gb/outlook/troubleshoot/extended-mapi-solutions/expose-permissions-issue-with-mapi-oauth-tokens
Please start treating the vendors proactively and communicate with us about the solutions! Feel free to reach me at navara_at_emclient_dot_com, I will be happy to adapt the product for the mutual benefit of our customers. Right not we can support Modern Authentication only by limiting the features we offer.
Also, in response to our original support ticket (#14415384 on Microsoft 365 support) we were told this:
> At present we only support basic authentication for those resources. Should we ever decide to deprecate basic authentication, we will expose the necessary permissions to allow access but for the time being this is not something we're considering.
This did NOT happen.