Google Cloud Messaging (GCM)
Google Cloud Messaging (GCM) was a mobile notification service provided by Google that allowed developers to send data from servers to their Android applications, as well as receive messages from devices on a reliable and efficient platform. Introduced in 2012, GCM replaced the previous Android Cloud to Device Messaging (C2DM) service and provided enhanced features such as support for sending data payloads up to 4KB, upstream messaging for sending data from devices to servers, and device group messaging for managing groups of devices efficiently. GCM played a crucial role in enabling push notifications, remote configuration updates, and data synchronization in Android applications, enhancing user engagement and experience. However, GCM was deprecated in April 2018, and developers were encouraged to migrate to the newer Firebase Cloud Messaging (FCM) service, which offered additional features and broader platform support, including iOS devices and web applications. s://developers.google.com/cloud-messaging