Silent push for iOS

XCode → Signing & Capabilities → Background modes
Depends what you want to achieve with silent push, turn on Background fetch or Background processing or both.

At AppDelegate file you need to add those two methods to handle silent push content.

func application(_ application: UIApplication, performFetchWithCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        print("perform fetch completition")
        Appoxee.shared()?.performFetch(completionHandler: nil, andNotifyCompletionWith: { (error, data) in
            if (NSNumber.isKind(of: data as! AnyClass)) {
                print(data ?? "no date");
                completionHandler(.newData)
            }
            completionHandler(.noData)
        })
    }
    
    func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
        print(userInfo)
        Appoxee.shared()?.didReceiveRemoteNotification(userInfo, fetchCompletionHandler: completionHandler, andNotifyCompletionWith: { (error, data) in
            if ((error) != nil) {
                completionHandler(.failed)
            } else {
                //// No need to pefrom any action, since Appoxee will call completionHandler() providing it a UIBackgroundFetchResult.
            }
        })
    }