xwords/xwords4/android/build.gradle

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

buildscript {
    repositories {
        jcenter()
        maven { url 'https://maven.fabric.io/public' }
        google()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.2'
        classpath 'io.fabric.tools:gradle:1.+'

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

allprojects {
    repositories {
        jcenter()
    }
}

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

subprojects {
    afterEvaluate {project ->
        if (project.hasProperty("android")) {
            android {
                compileSdkVersion 23
            }
        }
    }
}