Currently only delegated user permissions are supported, and this is very sub-optimal for bots and service applications that need to monitor Teams presence of users.
We route calls based on presence status, for our customers. Polling MS Graph API for Teams presence status with tens of thousands of users in multiple AD's, is not a feasible solution and according to the documentation: it's a bannable offence.
It would be great to have the ability to use the subscription API with the client credentials grant. Would be a considerable boost for us developers and our customers, to not have a complex authentication process.
jh7459I doubt that is the case, there are plenty of businesses who do not want to migrate from Skype to Teams, just because of lack of functionality or API support. This is mostly due to limited resources (time, personnel) and design choices.