Hello, I am investigating call behaviour on a dual SIM iPhone. Observed behavior: A specific line is selected in Settings > Cellular > Default Voice Line. Our app initiates the native call flow by opening a phone-number URL scheme with the destination number. The native Phone app does not always place the call using the selected default line. Expected behaviour: The native Phone app should place the call using the line selected in Settings > Cellular > Default Voice Line Questions: In this flow, is line selection fully controlled by iOS? Is there any supported way for an app to ensure the native Phone app respects the selected default line? Is this a known limitation or known issue on dual SIM devices? Any clarification on expected iOS behaviour would be appreciated.

Hello! Our app includes a calling feature for some users, and we would like to promote to those users that they can set our app as their default calling app. If there is no way to check this state, then the risk is that we may repeatedly prompt users to enable something they have already enabled. There also doesn't appear to be a way to set the default calling app programmatically, and that the best we can do may be to direct the user to the default app section in Settings. For our app, the calling capability is only applicable to some users. For users who are not eligible to place calls, we would prefer that they not be able to set our app as the default calling app at all. Otherwise, iOS may route calling actions to our app. So my questions are: Is there any supported API or other mechanism to determine whether the user has set our app as their default calling app? Is there any supported way to enable, disable, or hide default calling app eligibility programmatically? My current understanding is that neither of these is possible, but I would appreciate confirmation or any recommended workaround. Thanks.

Hello! I’m building a VoIP app for iPhone and Apple Watch using PushKit and CallKit. I’m trying to understand the recommended watchOS architecture for this kind of setup. What we would like is for the watch to behave as an endpoint for incoming calls, so that when a call comes in the user can answer on either the iPhone or the watch. My understanding is that VoIP notifications are not supported on watchOS, so for incoming calls what we ended up having to do was send the watch a regular APNs alert notification and only start the actual call setup after the user interacts with it. This isn’t ideal, and the notification often appears a few seconds late. What we would like to be able to do is present the incoming call on the watch more like how FaceTime calls appear on Apple Watch. So I wanted to ask whether this is the intended pattern for a companion watchOS VoIP app. Is using a regular APNs alert notification the correct way to surface an incoming call on the watch, or is there a better supported approach? Thanks!