ring-android/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:2.3.1'
        classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}
allprojects {
    repositories {
        mavenCentral()
    }
}

dependencies {
}
task wrapper(type: Wrapper) {
    gradleVersion = '3.3' //version required
}