Push Notification issue in iOS 13 - ios

Question

I am using Remote Push Notification feature in my iOS application. Currently i am facing a strange issue. I am receiving push notifications into devices which are have iOS < 13 but those devices which are have iOS 13 not getting push notifications.
I searched a lot over stackoverflow and other platform and found that apple suggested that in iOS 13 we need to add "apns-push-type" into header as well as in payload body. I have done it over server side where i write push notifications related code.
I developed my application using XCode 11 and using FCM (Firebase Cloud Messaging) service to send push notifications.
public function pushSurveyorNotificationios(){
$url = "https://fcm.googleapis.com/fcm/send";
$token = 'XXXX-XXXXX-XXXXX';
$serverKey = 'XXXX-YYYYY-ZZZZZ';
$title = "Push Notification Testing";
$body = "Push Notification Testing detail";
$notification = array('title' =>$title , 'body' => $body, 'sound' => 'default', 'badge' => '1');
$arrayToSend = array('to' => $token, 'notification' => $notification, 'apns' => array('headers' => array('apns-push-type' => 'alert')));
$json = json_encode($arrayToSend);
//die($json);
$headers = array();
$headers[] = 'apns-push-type: alert';
$headers[] = 'Content-Type: application/json';
$headers[] = 'Authorization: key='. $serverKey;
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $url);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST,
"POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, $json);
curl_setopt($ch, CURLOPT_HTTPHEADER,$headers);
//Send the request
$response = curl_exec($ch);
//Close request
if ($response === FALSE) {
die('FCM Send Error: ' . curl_error($ch));
}
curl_close($ch);
return $response;
}
Above function i am using to send push notifications to devices.
I got this link over apple for iOS 13 push notifications issue.
https://developer.apple.com/forums/thread/118420