Issue starting Live Activities with ActivityKit push notifications

After downloading Xcode 15.1 RC I can get it to work on my device (updated with the latest beta), still not working in the simulator.

The only way I found to get the token to update a live activity created through a push notification was to put the following code in my AppDelegate application didFinishLaunchingWithOptions method. I'm able to update a live activity created using push notifications using the token from pushTokenUpdates.

But there is a major design flow IMO, since you can start a live activity without your app being running the following code will never get hit in that instance, and without a way to retrieve the update token from the server side there will be no way of updating the live activity...

I must be missing something but the doc is not helpful in its current state.

Task {
            //
            // Wait for newly created live activities
            //
            for await activityData in Activity<DailyGoalActivityAttributes>.activityUpdates {
                Task {
                    //
                    // Wait for the token needed to update a live activity using push notifications.
                    //
                    for await tokenData in activityData.pushTokenUpdates {
                        let token = tokenData.map {String(format: "%02x", $0)}.joined()
                        print("Push token: \(token)")
                    }
                }
            }
        }

Regarding the payload, here is a working example:

curl -v \
  --header "authorization: bearer ${AUTHENTICATION_TOKEN}" \
  --header "apns-topic: com.yourcompany.app.ios.push-type.liveactivity" \
  --header "apns-push-type: liveactivity" \
  --header "apns-priority: 10" \
  --header "apns-expiration: 0" \
  --data '{"aps":{"timestamp":'$(date +%s)', "event":"start", "content-state": {"currentValue":40000,"targetValue":50000}, "attributes-type":"MyActivityAttributes","attributes":{"currentValue":40000,"targetValue":50000},"alert":{"title":"Almost there!","body":"You have reached 75% of your goal!"}}}' \
  --http2  https://api.development.push.apple.com:443/3/device/${PUSH_TO_START_TOKEN}

From my experience, it seems that pushToStartTokenUpdates, and similarly pushToStartToken, will only trigger on a fresh app install + having rebooted your device + calling this method in didFinishLaunchingWithOptions, and it has to be that specific combination all at once. That means:

1. Uninstalling and reinstalling the app will not trigger this token again.
2. Simply restarting your device without reinstalling the app will also not trigger this token.
3. If you call this stream in didFinishLaunchingWithOptions, you'll never get the token again unless steps 1 & 2 are also taken first.

This doesn't seem like ideal behavior, as there may be a situation where my application may not be ready to process that push-to-start token. Basically, if my user misses that window to retrieve and process the token, they'll basically never be able to receive a Live Activity. I imagine this is a bug and hopefully gets resolved sooner rather than later.

I realise I’m piling on here, but this thread seems to be the only place on the Internet where this functionality is being discussed.

Where there are static attributes of your ActivityAttributes class, how are you reflecting those in the push to start payload? The example provided by Apple is a little confusing as it has the same model for content-state and attributes.

Could anybody provide insight on how exactly the Live Activity is created via the push notification. Apple's docs state "When the system receives the ActivityKit push notification on a device, it starts a new Live Activity, wakes up your app, and grants it background run time to allow you to download assets that the Live Activity needs." Can anybody elaborate on how/where exactly this happens?

I'm able to successfully obtain the pushToStartToken and can successfully deliver APNS payload via CloudKit - Push Notifications tool. I see in the delivery logs that my push notification was both received by the APNS server and successfully delivered to target device. Once delivered, I see my pushToStartTokenUpdates trigger once more and can get an updated token but, I don't fully understand how/where the live activity is actually created. Any information would be much appreciated

I was experiencing this same issue. To resolve, I added this to my info.plist file. Supports Live Activities: YES

After doing this, I immediately started receiving the token on the next call.