This is my **Gradle** file as you can see I have the minimum SDK to 19:

```
android {
    compileSdkVersion 26
    buildToolsVersion '27.0.3'
    defaultConfig {
        minSdkVersion 19
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        vectorDrawables.useSupportLibrary = true
    }

buildTypes {
    release {
        minifyEnabled false

        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:26.1.0'
    implementation 'com.android.support:support-v4:26.1.0'
}

```

Android studio gives me this error:

```
android:interpolator="@android:interpolator/fast_out_slow_in requires API level 21 (current min is 19)

```

If I change the minimum SDK to 21 it works, but I want to be able to support minimum SDK of 19 at least.