Version conflict updating to 8.4.0

Use these dependencies for the project build.gradle

dependencies {
    classpath 'com.android.tools.build:gradle:2.0.0-alpha3'
    classpath 'com.google.gms:google-services:2.0.0-alpha3'
}

and put this at the end of the app-level build.gradle file (after the dependencies).

apply plugin: 'com.google.gms.google-services'

I have no clue why putting this at the end (and not at the beginning ) solves the error.

EDIT 5/1/2016

Ok… So trying to put an end to all problems you guys have faced with my solution

This is my final app level gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "your-app-name"
        minSdkVersion 16
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

repositories {
    jcenter()
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.google.android.gms:play-services:8.4.0'
    compile 'com.android.support:design:23.1.1'
    compile 'com.mcxiaoke.volley:library:1.0.6@aar'
}

apply plugin: 'com.google.gms.google-services'

and this is my final project level 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 {
        jcenter()
    }
}

Compare this with your own gradle files, and add or modify any values which are different from what I've written.

In the application's module (build.gradle)

Moving :

apply plugin: 'com.google.gms.google-services'

to the last line solved the issue.

Do the following:

1. Put the following in your build.gradle(Application level gradle file)

   dependencies {
         classpath 'com.android.tools.build:gradle:2.0.0-beta2'
         classpath 'com.google.gms:google-services:2.0.0-beta2'
   }
   

Please check here for latest version as this keep on changing.

2. If you get the below error message than you need to upgrade your gradle wrapper to latest in gradle-wrapper.properties. I'm using 2.10.

Plugin is too old, please update to a more recent version, or set ANDROID_DAILY_OVERRIDE environment variable

3. Put the following line at the bottom of your build.gradle(module level gradle file)

   apply plugin: 'com.google.gms.google-services
   

This seems to be fixed with version 3.0.0 of Google Services plugin (and version 9.0.0 of the Google Play Services library). So with this

top level build.gradle

dependencies {
    classpath 'com.google.gms:google-services:3.0.0'
}

app level build.gradle

apply plugin: 'com.google.gms.google-services'

dependencies {
    compile 'com.google.android.gms:play-services:9.0.0
}

Quick Side Note: If you are updating to version 3.0.0 of the google-services plugin, make sure to regenerate your configuration file as it has new fields (explained here).

Edit (2016-06-20): While this does compile and run, I just noticed that in the build logs it does specify to put the plugin at the bottom of the file, or the default (9.0.0) will be used. So in the situation above this isn't a problem since I am using version 9.0.0, but this can be problematic when updating the dependency. Here's the log:

google-services plugin could not detect any version for com.google.android.gms or com.google.firebase, default version: 9.0.0 will be used. please apply google-services plugin at the bottom of the build file.