Application - Software Development Kit (SDK)
SDKs match API level. When a new API level is released, a new SDK is released to make projects for that level
compiledSdkVersion is the platform version against which you will compile your app. By default, this is set to the latest version of Android available in your SDK. You can still build your app to support older versions, but setting this to the latest version allows you to enable new features and optimize your app for a great user experience on the latest devices.
minSdkVersion is the Minimum SDK version you specified during the New Project workflow. This is the earliest version of the Android SDK that your app supports.
targetSdkVersion indicates the highest version of Android with which you have tested your application. As new versions of Android become available, you should test your app on the new version and update this value to match the latest API level and thereby take advantage of new platform features.