Android Studio 2.3 Generar Apk firmado Verificación de firma de segundo paso v1 (Firma de tarro), v2 (Firma de Apk completo) ¿Cómo se habilita?

Captura de pantalla firmada de Apk Second Step debajo de los archivos gradle:

Mi archivo build.gradle es: -

 android { compileSdkVersion 25 buildToolsVersion '25.0.2' dataBinding { enabled = true } defaultConfig { applicationId 'com.revolution.it' minSdkVersion 15 targetSdkVersion 25 versionCode 1 versionName "1.0" testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" vectorDrawables.useSupportLibrary true multiDexEnabled true } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } debug { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro' } } productFlavors { } } dependencies { compile fileTree(include: ['*.jar'], dir: 'libs') androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' }) androidTestCompile 'com.android.support.test.espresso:espresso-contrib:2.2.2', { exclude group: 'com.android.support', module: 'support-annotations' exclude group: 'com.android.support', module: 'support-v4' exclude group: 'com.android.support', module: 'design' exclude group: 'com.android.support', module: 'recyclerview-v7' } compile 'com.android.support:appcompat-v7:25.1.0' compile 'com.android.support:design:25.1.0' compile 'com.android.support:support-v4:25.1.0' compile 'com.squareup.retrofit2:retrofit:2.1.0' compile 'com.squareup.retrofit2:converter-gson:2.1.0' compile 'com.squareup.okhttp3:logging-interceptor:3.3.1' compile 'uk.co.chrisjenx:calligraphy:2.2.0' compile 'org.greenrobot:eventbus:3.0.0' compile 'com.squareup.picasso:picasso:2.5.2' compile 'com.google.firebase:firebase-messaging:10.0.1' compile 'com.google.firebase:firebase-crash:10.0.1' compile 'org.apache.directory.studio:org.apache.commons.io:2.4' // Image and file picker compile 'com.droidninja:filepicker:1.0.8' compile 'com.android.support:multidex:1.0.1' compile 'com.google.android.gms:play-services-location:10.0.1' testCompile 'junit:junit:4.12' debugCompile 'com.amitshekhar.android:debug-db:1.0.0' } apply plugin: 'com.google.gms.google-services'