Kamil Skorski (Microsoft) notes in a post on GitHub that the Microsoft Teams Calling API's are scheduled for GA in the June/July timeframe and "We're working on finalizing the APIs now".
There are no more public clarifications. Does this mean the currently available API's will merely get the designation of "GA"? Or something more to come?
A key component that is missing for many uses of the Calling API is the ability for users to dial into a Microsoft Teams app from PSTN.
The Microsoft Teams Calling API Previewed at Microsoft Ignite 2018.
Source:
https://github.com/microsoftgraph/microsoft-graph-comms-samples/issues/62#issuecomment-492318404
