Eu uso o Firebase como back-end. Também uso o FCM como um dos recursos fornecidos pelo Firebase. O FCM funcionou bem no iOS 10, mas depois de mudar para o iOS 11, as notificações push pararam de chegar aos dispositivos do usuário, e eu próprio não recebi nenhuma notificação push enviada das funções da nuvem ou da seção Notification no Firebase Console. Como consertar esse problema?

Atualizar: Enviei várias notificações push do Firebase Notifcations, mas elas não vêm.

// MARK: - Push notification

extension AppDelegate: UNUserNotificationCenterDelegate {

    func registerPushNotification(_ application: UIApplication) {
        // For iOS 10 display notification (sent via APNS)
        UNUserNotificationCenter.current().delegate = self

        let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
        UNUserNotificationCenter.current().requestAuthorization(
            options: authOptions,
            completionHandler: {_, _ in })

        // For iOS 10 data message (sent via FCM)
        Messaging.messaging().delegate = self
    }

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        //When the notifications of this code worked well, there was not yet.
        Messaging.messaging().apnsToken = deviceToken
    }

    // [START receive_message]
    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any]) {
        // If you are receiving a notification message while your app is in the background,
        // this callback will not be fired till the user taps on the notification launching the application.
        // TODO: Handle data of notification
        // Print message ID.
        if let messageID = userInfo[gcmMessageIDKey] {
            debugPrint("Message ID: \(messageID)")
        }

        // Print full message.
        debugPrint(userInfo)
    }

    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any],
                     fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        // If you are receiving a notification message while your app is in the background,
        // this callback will not be fired till the user taps on the notification launching the application.
        // TODO: Handle data of notification
        // Print message ID.
        if let messageID = userInfo[gcmMessageIDKey] {
            print("Message ID: \(messageID)")
        }

        // Print full message.
        debugPrint(userInfo)

        completionHandler(.newData)
    }

    // showing push notification

    func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: @escaping () -> Void) {
        if let userInfo = response.notification.request.content.userInfo as? [String : Any] {
            let routerManager = RouterManager()
            routerManager.launchRouting(userInfo)
        }
        completionHandler()
    }

    func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        if let userInfo = notification.request.content.userInfo as? [String : Any] {
            if let categoryID = userInfo["categoryID"] as? String {
                if categoryID == RouterManager.Categories.newMessage.id {
                    if let currentConversation = ChatGeneralManager.shared.currentChatPersonalConversation, let dataID = userInfo["dataID"] as? String  {
                        // dataID is conversationd id for newMessage
                        if currentConversation.id == dataID {
                            completionHandler([])
                            return
                        }
                    }
                }
            }
            if let badge = notification.request.content.badge {
                AppBadgesManager.shared.pushNotificationHandler(userInfo, pushNotificationBadgeNumber: badge.intValue)
            }
        }
        completionHandler([.alert,.sound, .badge])
    }

}

// [START ios_10_data_message_handling]
extension AppDelegate : MessagingDelegate {

    func messaging(_ messaging: Messaging, didRefreshRegistrationToken fcmToken: String) {
        let pushNotificationManager = PushNotificationManager()
        pushNotificationManager.saveNotificationTokenInDatabase(token: fcmToken, success: nil, fail: nil)
    }


    // Receive data message on iOS 10 devices while app is in the foreground.
    func application(received remoteMessage: MessagingRemoteMessage) {
        debugPrint(remoteMessage.appData)
    }

}