Firebase Cloud Messaging (FCM) is the new version of GCM. Link to Google https://developers.google.com/cloud-messaging/
- Send Payload Push
Please check the box before creating your app for this feature to be enabled in the app
- GCM API Key
Enter the server key here
- GCM Sender ID
Enter your Sender ID (a multi-digit numeric value).
Select Save. Lastly, the app must be rebuilt so that the changes are effective in the app.