Google Cloud Messaging (GCM) Technology (Push notifications android)

Another question, Whether Google Cloud Messaging support iOS?
There were email asking Google Cloud Messaging for android (GCM) Sample tutorials, AMD can you prepare a few tutorials on this topic? It will be helpful for CSE/IT engineers to practice a few projects with it.
Here are excerpts from a sample manifest that supports GCM used in client (the android APK: Complete reference can be found here:
<manifest package="com.example.gcm" ...>

    <uses-sdk android:minSdkVersion="8" android:targetSdkVersion="17"/>
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.GET_ACCOUNTS" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="" />

    <permission android:name="com.example.gcm.permission.C2D_MESSAGE"
        android:protectionLevel="signature" />
    <uses-permission android:name="com.example.gcm.permission.C2D_MESSAGE" />

    <application ...>
            android:permission="" >
                <action android:name="" />
                <category android:name="com.example.gcm" />
        <service android:name=".GcmIntentService" />

This is how these components interact:
[Image: GCM-arch.png]
Source: GCM Architectural view
As of April 10, 2018, Google has deprecated GCM. The GCM server and client APIs are deprecated and will be removed as soon as April 11, 2019. Migrate GCM apps to Firebase Cloud Messaging (FCM), which inherits the reliable and scalable GCM infrastructure, plus many new features.