Voip Pushkit notification will not re-launch the a

I cannot get voip pushkit notifications to re-launch the app if the user has force-quitted the app (by swiping it up in the multi-tasking interface) AND if the device was rebooted.

However, I can get the voip pushkit notifications to work in the following scenarios:

The app was force-quitted then the pushkit notification arrives. The app will be relaunched immediately. Standard push notifications are not capable of waking the app in such scenario.
The app was in the background / suspended and the device is rebooted. Thanks to Voip mode, the app will be relaunched on device reboot (I can see the process in Xcode Activity Monitor). There is a trick needed here to get the pushkit notification to be properly processed which is described in http://blog.biokoda.com/post/114315188985/ios-and-pushkit in these terms "Before initializing PushKit start a background task. Finish this task when PushKit token is received"

Somehow when combining these two (device reboot AND app force-quit) then pushkit notifications doesn't seem to relaunch the app. Also when looking at the device logs in Xcode I get no logs from apsd saying the notification was processed by the system.

Here is my code:

@implementation AppDelegate
{
  UIBackgroundTaskIdentifier bgTask;
}
- (BOOL)application:(UIApplication *)application 
    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    UIApplication* app = [UIApplication sharedApplication];
    bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
        [app endBackgroundTask:bgTask];
        bgTask = UIBackgroundTaskInvalid;
    }];
    dispatch_async(dispatch_get_global_queue(
    DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        while (true) {
            ;
        }
    });
    // Initialize pushkit
    PKPushRegistry *pushRegistry =
        [[PKPushRegistry alloc] initWithQueue:dispatch_get_main_queue()];
    pushRegistry.delegate = self;
    pushRegistry.desiredPushTypes = [NSSet setWithObject:PKPushTypeVoIP];    
    return YES;
}

- (void)pushRegistry:(PKPushRegistry *)registry 
    didUpdatePushCredentials:(PKPushCredentials *)credentials
    forType:(NSString *)type{
    UIApplication* app = [UIApplication sharedApplication];
    [app endBackgroundTask:bgTask];
    // ... more code to read the token ...
}

- (void)pushRegistry:(PKPushRegistry *)registry
    didReceiveIncomingPushWithPayload:(PKPushPayload *)payload
    forType:(NSString *)type {
    // ... logging to check if notification is received ...
}

Also I have "Voice over IP" and "Remote notifications" enabled in Background modes.

I know other apps like Whatsapp are capable of being relaunched in this scenario, so I don't understand what I am doing wrong.

On a related note, it doesn't help to do the following 1) Force quit 2) Send a pushkit notification - which will be received 3) Reboot. The app will not be relaunched and a new push notification will still not relaunch it.

After I tested the app with an AdHoc provisioning profile (and installed it from iTunes), the Voip push notifications served through prod gateway.push.apple.com instead of gateway.sandbox.push.apple.com started waking up the force-quitted app after reboot.

The os is apparently handling development and production in a different manner.

Looking further into the APSD logs, I found that when using a development provisioning profile the following is printed out: