title: Cannot resolve issue regarding backward compatibility library
body: <p>I have Android Studio 3.1.2 Latest Updated .</p>
  
  <p>I got an issue with Backward Compatibility as seen in image </p>
  
  <p><a href="https://i.stack.imgur.com/0n4r6.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0n4r6.png" alt="Issue Image "></a></p>
  
  <p>Below is my gradle File </p>
  
  <p>Gradle File : </p>
  
  <pre><code>apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 27
      defaultConfig {
          applicationId "com.companyname.appname"
          minSdkVersion 21
          targetSdkVersion 27
          versionCode 1
          versionName "1.0"
          testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
      }
      buildTypes {
          release {
              minifyEnabled false
              proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
          }
      }
  }
  
  dependencies {
      implementation fileTree(dir: 'libs', include: ['*.jar'])
      implementation 'com.android.support:appcompat-v7:27.1.1'
      implementation 'com.android.support.constraint:constraint-layout:1.1.0'
      testImplementation 'junit:junit:4.12'
      androidTestImplementation 'com.android.support.test:runner:1.0.2'
      androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
  
      implementation 'com.android.support:appcompat-v7:27.1.1'
      implementation 'com.android.support:design:27.1.1'
      testCompile 'junit:junit:4.12'
      implementation 'com.android.support:multidex:1.0.1'
      implementation 'com.android.support:cardview-v7:27.1.1'
  
      implementation 'com.google.android.gms:play-services:9.2.0'
      implementation files('libs/ksoap2-android-assembly-2.4-jar-with-dependencies.jar')
      implementation('com.crashlytics.sdk.android:crashlytics:2.6.6@aar') {
          transitive = true;
      }
      implementation 'com.weiwangcn.betterspinner:library-material:1.1.0'
  
  
  }
  </code></pre>
  
  <p>The above is my gradle file , I am not using the library as described in Error , still getting error .</p>