Im having a problems when trying to implement gcm. When I try to sync gradle files this error appears:

```
Warning:Gradle version 2.8 is required. Current version is 2.4. If using the gradle wrapper, try editing the distributionUrl in D:\MyProjects\Android\Enjoy\gradle\wrapper\gradle-wrapper.properties to gradle-2.8-all.zip

```

Tried to go to wrapper and change it to 2.8, but its still not working.

Here is my app build.gradle:

```
apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "enjoy.enjoyprague_restaurants_bars"
        minSdkVersion 17
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    packagingOptions {
        exclude 'META-INF/LICENSE.txt'
        exclude 'META-INF/NOTICE.txt'
    }
    dexOptions {
        javaMaxHeapSize "4g"
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
//    android libraries activity, design
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.android.support:design:23.1.1'
    compile 'com.android.support:cardview-v7:23.1.1'
    compile 'com.android.support:recyclerview-v7:23.1.1'

//    application
    compile 'com.android.support:multidex:1.0.1'

//    volley for handlers
    compile 'com.mcxiaoke.volley:library:1.0.19'
    compile 'com.google.code.gson:gson:2.4'

//    picasso
    compile 'com.squareup.picasso:picasso:2.5.2'

//    simple xml
    compile('org.simpleframework:simple-xml:2.7.1') {
        exclude group: 'stax', module: 'stax-api'
        exclude group: 'xpp3', module: 'xpp3'
    }

//    floating action menu
    compile 'com.oguzdev:CircularFloatingActionMenu:1.0.2'

//    Google Map api
    compile 'com.google.android.gms:play-services:8.4.0'
    compile 'com.google.android.gms:play-services-gcm:8.4.0'
    compile 'com.google.maps.android:android-maps-utils:0.4'
}
//google gcm sender
apply plugin: 'com.google.gms.google-services'

```

and top level build gradle:

```
// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.0.0-alpha3'
        classpath 'com.google.gms:google-services:2.0.0-alpha3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        maven { url "http://dl.bintray.com/populov/maven" }
        mavenCentral()
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

```