Hello Apple Developer Community, We're implementing the PushToTalk framework as recommended. According to Apple engineers in previous forum responses : the framework allows your app to continue receiving push notifications even after your app is terminated or the device is rebooted. Implementation: We've properly implemented: Early initialization of PTChannelManager via channelManager(delegate:restorationDelegate:completionHandler:) Channel joining with requestJoinChannel(channelUUID:descriptor:) when foregrounded All required delegate methods Issue After a user force quits our app, PushToTalk functionality works briefly but fails after some time (minutes to hours). The system logs show: AudioSessionServerImpCommon.mm:105 { "action":"cm_session_begin_interruption", "error":"translating CM session error", "session":{"ID":"0x72289","name":"getcha(2958)"}, "details":{ "calling_line":997, "error_code":-12988, "error_string":"Missing entitlement" } } We suspect that entitlement after force-quitting the app, there's a permission cache that temporarily allows functionality, but once this cache is cleared, the features stop working. Without this entitlement, both audio playback and recording fail, completely breaking the PTT functionality. Questions Which specific entitlement is missing according to this error? Is there a permission caching mechanism that expires after force quit? How can we ensure reliable PTT operation after force quit as stated in documentation? This behavior contradicts Apple's guidance that PushToTalk should work reliably after termination. Any insights would be greatly appreciated. Thank you!

PLATFORM AND VERSION: iOS Development environment: Other: .net MAUI with vscode Run-time configuration: iOS 18.1.1 DESCRIPTION OF PROBLEM APNS notifications of apns-push-type pushtotalk sometimes stop arriving after switching networks. STEPS TO REPRODUCE We have created a simple app which can be used to deminstrate this issue. When you launch the app it displays the APNS token which you can then use fromn the Apple Push Console to manually send it PTT push notifications. https://github.com/trampster/PttPushNotificationIssue On an iPhone SE (we havn't been able to reproduce on our iPhone 11) Start the APP to register for the APNS push notifications Turn off the WiFi wait for 5 seconds Attempt a push to the app manually using the Push Notifications Console (this should fail, which is fine) Turn on Cellular and wait for it to connect Attempt to push to the app manually using the Push Notifications Console -> This fails, and all attempts to send an pushtotalk push notifications fail until the we switch network again. Send a push while offline before connecting to the new network seems to make it happen more often but hard to tell for sure. The results of the failed push in the console look like this: Delivery LogLast updated: 30/01/25, 16:45:06 GMT+13 Refresh 30 Jan 2025, 16:45:03.661 GMT+13 received by APNS Server 30 Jan 2025, 16:45:03.662 GMT+13 discarded as device was offline The device is actually very much online. Switching networks again oftern makes things come right. But it doesn't seem to come right by itself. We can't respond to network changes and do anything as the whole point of using push-to-talk push notifications is to wake up the app when in the background to answer a call, this means we are not running and therefore cannot respond to network changes to try to work arround this issue.

Hello everyone, Our team is currently developing an iOS application requiring real-time audio communication and evaluating the most suitable frameworks. Options include CallKit, custom solutions using AVAudioEngine/Audio Units, and the PushToTalk framework. Regarding the PushToTalk framework, we have some questions about its core design and capabilities that we'd appreciate clarification on from the community or Apple engineers. Based on the PushToTalk framework documentation, its API design (e.g., methods like requestBeginTransmission, endTransmission which imply explicitly requesting transmission rights), and its system UI integration, it strongly appears oriented towards half-duplex communication scenarios, similar to traditional walkie-talkies where only one participant transmits audio at a time. Is this understanding accurate? Is the PushToTalk framework's design strictly limited to managing half-duplex audio interactions? Or, does the framework itself also provide built-in mechanisms or APIs to manage simultaneous, bi-directional (full-duplex) audio streaming between participants? To be clear, we are asking about the inherent capabilities of the PushToTalk framework itself. We understand it's possible to use PushToTalk for signaling and UI management, and separately implement the actual full-duplex audio stream using AVAudioEngine or other audio APIs. However, we want to confirm if the framework itself is designed to support or simplify full-duplex audio communication. Have other developers investigated the specific limitations or capabilities of the PushToTalk framework regarding audio transmission modes (half-duplex vs. full-duplex)? Are there any official documentation references or WWDC sessions that explicitly clarify the framework's support (or lack thereof) for full-duplex operation? If PushToTalk is indeed limited to half-duplex, what are the generally accepted best practices for apps requiring full-duplex calls – transitioning directly to CallKit (where applicable) or building custom audio processing pipelines? Clarifying this point is crucial for us to select the correct technology stack for our application. Any relevant insights, documentation pointers, or shared development experiences would be greatly appreciated. Thank you for your help!

We are attempting to update our app to use the PTT framework, as it has been made clear that this will be required in a future iOS version as opposed to using the Unrestricted VoIP entitlement we are using for several features of our app. However, the behavior of this framework poses some problems with implementing our app's functionality: It is not possible to programmatically join a channel when the app is not in the foreground. This hinders our ability to implement the Automatically activate radio stream feature of our app, which allows users who have opted into this feature to immediately begin hearing live PTT audio from their agency following an incident alert. Having the app constantly "joined to a channel" and using the restoration delegate could potentially work, however this is not ideal as this would result in the PTT UI needing to be displayed at all times, even when no radio stream is activated. We have a "Text to Speech" option that, when enabled, reads out the content of an incident alert after the alert sound has played. This currently happens by triggering an AVSpeechSynthesizer in the PushKit incoming push callback. It may be possible to render TTS audio on the fly in a Notification Service Extension and assign it as the notification's sound, if that is possible this is less of a problem. We also use the PushKit callback to, again if the user has enabled it, activate a "Shake to Respond" feature, allowing a short period of time after receiving an incident alert in which the user can shake their device to indicate that they are responding to the incident. There does not appear to be any way to have the level of background execution required to implement this using an NSE, and this is of course beyond the scope of the PTT framework. What options do we have to be able to continue to provide this functionality, without risk of it being disabled in a future iOS version?

As I've mentioned before our app uses PTT Framework to record and send audio messages. In one of supported by app mode we are using WebRTC.org library for that purpose. Internally WebRTC.org library uses Voice-Processing I/O Unit (kAudioUnitSubType_VoiceProcessingIO subtype) to retrieve audio from mic. According to https://developer.apple.com/documentation/avfaudio/avaudiosession/mode-swift.struct/voicechat using Voice-Processing I/O Unit leads to implicit enabling .voiceChat AVAudioSession mode (i.e. it looks like it's not possible to use Voice-Processing I/O Unit without .voiceChat mode). And problem is following: when user starts outgoing PTT, PTT Framework plays audio notification, but in case of enabled .voiceChat mode that sound is playing distorted or not playing at all. Questions: Is it known issue? Is there any way to workaround it?

We have application using PTT Framework to record audio messages when app is backgrounded. Right now we are using AVAudioRecorder for that purpose. And problem is one specific user has frequent issue - recorded audio contains only silence. I've checked almost everything I can imagine but didn't find any possible reason of issue. Conditions: AVAudioRecorder uses following configuration: [ AVEncoderAudioQualityKey: AVAudioQuality.low.rawValue, AVFormatIDKey : kAudioFormatMPEG4AAC, AVNumberOfChannelsKey: 1, AVSampleRateKey: 16000.0 ] App waits both didBeginTransmitting and didActivate audioSession from PTChannelManager (audio session has playback category at that moment) App does AVAudioSession category change to playAndRecord App gets routeChangeNotification with categoryChange and category = playAndRecord There is no any interruption notifications from AVAudioSession during recording There is no any error notification from AVAudioRecorder Any idea what exactly I do wrong? Is there anything else I should check? Thanks in advance. P.S. it looks like recording audio with AudioUnit has the same issue, but let's exclude it from question atm for simplicity.