Firebase Push Notification `deprecatedEndPoint` Error

I am getting DeprecatedEndPoint error when I am trying to send notification from PHP server.

I am using 'com.google.firebase:firebase-messaging:11.8.0' for FCM.

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    //noinspection GradleCompatible
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    //noinspection GradleCompatible
//    implementation 'com.google.firebase:firebase-messaging:17.3.4'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    //noinspection GradleCompatible
    implementation 'com.google.firebase:firebase-auth:11.8.0'
    implementation 'com.google.firebase:firebase-core:11.8.0'
    implementation 'com.google.firebase:firebase-messaging:11.8.0'

    implementation 'com.google.android.gms:play-services-auth:8.3.0'
    //noinspection GradleCompatible
    implementation "com.google.android.gms:play-services-gcm:9.2.1"
}

and below is my firebase java class which i have declared in my manifest file:

public class MyFirebaseMessagingService extends FirebaseMessagingService {
    private static final String TAG = MyFirebaseMessagingService.class.getSimpleName();
    private String CHANNEL_ID = "1234";
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {

        final Uri alarmSound = Uri.parse("android.resource://com.clickaway.notificationdemo.pushnotificationdemo/raw/customsound");

        NotificationCompat.Builder notificationBuilder = (NotificationCompat.Builder) new NotificationCompat.Builder(this, CHANNEL_ID)
                .setContentTitle(remoteMessage.getNotification().getTitle())
                .setContentText(remoteMessage.getNotification().getBody())
                .setPriority(NotificationCompat.PRIORITY_DEFAULT)
                .setStyle(new NotificationCompat.BigTextStyle())
                .setDefaults(DEFAULT_SOUND | Notification.DEFAULT_VIBRATE)
                .setSmallIcon(R.mipmap.ic_launcher)
                .setAutoCancel(true);
        NotificationManager notificationManager =
                (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(0, notificationBuilder.build());      
    }
}

Change your End point URL to this - https://fcm.googleapis.com/fcm/send