I can't change minSdkVersion from 21 to 19, what should I do?

Question

android studio

Here is the error that pops
up ERROR: Manifest merger failed : uses-sdk:minSdkVersion 19 cannot be smaller than version 21 declared in library [androidx.camera:camera-core:1.0.0-alpha02] C:\Users\USER\.gradle\ caches\transforms-2\files-2.1\84f22891c3330b1e0bbdca99b7730947\camera-core-1.0.0-alpha02\AndroidManifest.xml as the library might be using APIs not available in 19
Suggestion: use a compatible library with a minSdk of at most 19,
or increase this project's minSdk version to at least 21,
or use tools:overrideLibrary="androidx.camera.core" to force usage (may lead to runtime failures) help!!!

Answer 1

1. build clear project
2. manifest.xml

<manifest>
<uses-sdk android:minSdkVersion="21" android:targetSdkVersion="30"/>
<application
tools:overrideLibrary="androidx.camera.core"
/>
</manifest>

3.build.gradle.kts

defaultConfig {
        minSdk = 21
        targetSdk = 30
    }

3. invalid cache restart