Skygear has been using GCM for Android push notifications. Since GCM will be replaced by FCM on 11 April 2019, we’ve updated the Skygear server and the Skygear Android SDK to support FCM.
If you are using Skygear for Android push notifications, please follow this guide to migrate from GCM to FCM: https://docs.skygear.io/guides/push-notifications/android-migrate-fcm/. You also need to upgrade your Skygear server and Skygear Android SDK to v1.7.0 to use FCM.
Hit reply if you have any problems migrating from GCM to FCM. Our team is here to help!