FCM 仍然与 GCM 兼​​容，因为它是它的核心.所以切换到 FCM 端点 (https://fcm.googleapis.com/fcm/send) 发送通知时，您的应用程序版本仍应适用于具有 GCM 的应用程序.无需编写单独的程序.

FCM is still compatible with GCM, seeing as it is it's core. So switching to the FCM endpoint (https://fcm.googleapis.com/fcm/send) when sending your notification should still work for your app versions that have GCM. No need to write separate programs.