receive external Notifikation prior API 26

[wolfgangschneider]

I wrote an MAUI app receive external Notification using API 26+ and Channels. Now I want to use the app for Android 5,6 and 7 wich use API sdk less then 26. How to setup notification manager or something else to Lissen notifications?

I call on Android
Firebase.Messaging.FirebaseMessaging.Instance.SubscribeToTopic("My Topic")

and use the same code on sender but without channel

private async void SendNotification()
{
// Construct the message payload
var message = new Message()
{
Notification = new Notification
{
Title = "Pure Notification",
Body = "This is a pure Notification"
},
Topic = NotificatioonTopic,

      };

  var response = await FirebaseMessaging.DefaultInstance.SendAsync(message);

}