Multiple APK Support | Android Developers
Multiple APK support is a feature on Google Play that allows you to publish different APKs for your application that are each targeted to different device configurations. Each APK is a complete and independent version of your application, but they share the same application listing on Google Play and must share the same package name and be signed with the same release key. This feature is useful for cases in which your application cannot reach all desired devices with a single APK.
Android-powered devices may differ in several ways and it's important to the success of your application that you make it available to as many devices as possible. Android applications usually run on most compatible devices with a single APK, by supplying alternative resources for different configurations (for example, different layouts for different screen sizes) and the Android system selects the appropriate resources for the device at runtime. In a few cases, however, a single APK is unable to support all device configurations, because alternative resources make the APK file too big (greater than 50MB) or other technical challenges prevent a single APK from working on all devices.
Although we encourage you to develop and publish a single APK that supports as many device configurations as possible, doing so is sometimes not possible. To help you publish your application for as many devices as possible, Google Play allows you to publish multiple APKs under the same application listing. Google Play then supplies each APK to the appropriate devices based on configuration support you've declared in the manifest file of each APK.