Hello everyone, I’m an iOS developer working on a real-time communication app that supports VoIP calls using CallKit. The app has been in production for more than 5 years. Over the years, some users have occasionally reported that they do not receive incoming call pushes. We have tried multiple optimizations on both the client and server side, but the improvement has been limited. From Apple documentation and discussions online, I understand that iOS may restrict VoIP pushes if the system detects violations of VoIP push usage rules (for example, not presenting a CallKit call after receiving a VoIP push). However, the exact rules and thresholds for these violations are not clearly documented, so I’d like to ask a few questions to better understand the expected behavior. Below is a simplified description of our current call flow. Call Flow Caller When the user initiates a call: We do not use CallKit The call is handled entirely using a custom in-app call UI Callee When the user receives a call: Device locked or app in background A VoIP push wakes the app The app presents the CallKit incoming call UI App in foreground The server still sends a VoIP push The app first reports the call to CallKit After a very short delay, the app programmatically ends the CallKit call Then a custom in-app call UI is presented via the app's long connection The reason we always send a VoIP push (even when the app is in the foreground) is that we want to maximize call delivery reliability.