title: Warning: warning: Supported source version 'RELEASE_7' from annotation processor 'android.arch.lifecycle.LifecycleProcessor' less than -source '1.8'
body: <p>Trying to build a sample using Android Studio 3 Canary 5 with Architecture Components and Kotlin gives this warning.</p>
  
  <p>Can anyone tell me the reason?</p>
  
  <p>Thanks, Ove</p>
  
  <p>Edit #1:
  This is a sample made some time ago by Dan Lew</p>
  
  <p><a href="https://github.com/dlew/android-architecture-counter-sample" rel="noreferrer">https://github.com/dlew/android-architecture-counter-sample</a></p>
  
  <p>build.gradle:</p>
  
  <pre><code>apply plugin: 'com.android.application'
  apply plugin: 'kotlin-android'
  apply plugin: 'kotlin-kapt'
  
  android {
      compileSdkVersion 25
      buildToolsVersion rootProject.ext.buildToolsVersion
      defaultConfig {
          applicationId "net.danlew.counter"
          minSdkVersion 23
          targetSdkVersion 25
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  }
  
  dependencies {
      compile fileTree(dir: 'libs', include: ['*.jar'])
      androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
          exclude group: 'com.android.support', module: 'support-annotations'
      })
      compile "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
      compile "com.android.support:recyclerview-v7:${rootProject.ext.supportLibVersion}"
      compile "com.android.support:design:${rootProject.ext.supportLibVersion}"
      compile "com.android.support:cardview-v7:${rootProject.ext.supportLibVersion}"
      compile 'com.android.support.constraint:constraint-layout:1.0.2'
      testCompile 'junit:junit:4.12'
  
      compile "android.arch.lifecycle:extensions:${rootProject.archLifecycleVersion}"
      compile "android.arch.persistence.room:runtime:${rootProject.archRoomVersion}"
      compile "android.arch.persistence.room:rxjava2:${rootProject.archRoomVersion}"
      kapt "android.arch.lifecycle:compiler:${rootProject.archLifecycleVersion}"
      kapt "android.arch.persistence.room:compiler:${rootProject.archRoomVersion}"
      compile "org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
  
      String butterKnifeVersion = '8.5.1'
      compile "com.jakewharton:butterknife:$butterKnifeVersion"
      kapt "com.jakewharton:butterknife-compiler:$butterKnifeVersion"
  
      compile 'io.reactivex.rxjava2:rxjava:2.1.0'
  
      String daggerVersion = '2.10'
      compile "com.google.dagger:dagger:$daggerVersion"
      kapt "com.google.dagger:dagger-compiler:$daggerVersion"
  
      String rxBindingVersion = '2.0.0'
      compile "com.jakewharton.rxbinding2:rxbinding:$rxBindingVersion"
      compile "com.jakewharton.rxbinding2:rxbinding-kotlin:$rxBindingVersion"
  
      compile 'com.jakewharton.timber:timber:4.5.1'
  
      compile 'com.jakewharton.rxrelay2:rxrelay:2.0.0'
  }
  
  repositories {
      mavenCentral()
  }
  </code></pre>