PhoneLineTransportDevice API no longer works on Windows 22H2

Recently I discovered that starting Windows 11 22H2 (build 22621), PhoneLineTransportDevice API no longer works, which resulted in our app’s Calling feature no longer working.

The Calling feature currently relies on the PhoneLineTransportDevice API. The following is a brief description of how to use this API:

1. Enumerate a PhoneLineTransportDevice using either the DeviceWatcher or DeviceInformation.
2. Call PhoneLineTransportDevice.RegisterApp() to register the app with Windows for the associated PhoneLineTransportDevice.
3. Call PhoneLineTransportDevice.ConnectAsync().
4. Use PhoneLineWatcher to enumerate PhoneLine, similar to the DeviceWatcher.
5. Call PhoneLine.Dial() Note: Microsoft’s Your Phone (now called Phone Link) uses the same mechanism to implement the Calling feature as of 2020, not sure for now.

However, after upgrading to Windows 11 22H2 (build 22621), calling PhoneLineTransportDevice.RegisterApp() either results in non-functional or throws a System.UnauthorizedAccessException, even though PhoneLineTransportDevice.RequestAccessAsync() returns “Allowed”.

I tested Phone Link on my PC and verified that it works without any issues. Therefore, I am not sure why our app is experiencing this problem.

I am seeking assistance in resolving this issue. If the PhoneLineTransportDevice API is no longer usable, I am open to suggestions for alternative solutions.

[abusaadp]

I contacted Microsoft and they said they were not aware of this issue. After checking they said there is some permission issue with this API in Windows 11 and they will resolve it soon. So we must wait for Microsoft to resolve this issue. Thats why this API is working for PhoneLink app as it may not have this permission issue.

[abusaadp]

Has Microsoft made an official announcement that Bluetooth calling will not work in Windows 11? Or have they changed the API for Bluetooth calling?