1 # 4\. Application Packaging Compatibility 2 3 Devices implementations: 4 5 * [C-0-1] MUST be capable of installing and running Android .apk files as 6 generated by the aapt tool included in the 7 [official Android SDK]( 8 http://developer.android.com/tools/help/index.html). 9 * As the above requirement may be challenging, device implementations are 10 RECOMMENDED to use the AOSP reference implementation's package management 11 systemDevice implementations. 12 * [C-0-2] MUST support verifying .apk files using the 13 [APK Signature Scheme v2](https://source.android.com/security/apksigning/v2.html) 14 and [JAR signing]( 15 https://source.android.com/security/apksigning/v2.html#v1-verification). 16 * [C-0-3] MUST NOT extend either the 17 [.apk](http://developer.android.com/guide/components/fundamentals.html), 18 [Android Manifest]( 19 http://developer.android.com/guide/topics/manifest/manifest-intro.html), 20 [Dalvik bytecode](https://android.googlesource.com/platform/dalvik/), or 21 RenderScript bytecode formats in such a way that would prevent those files from 22 installing and running correctly on other compatible devices. 23 * [C-0-4] MUST NOT allow apps other than the current 24 "installer of record" for the package to silently uninstall the app without any 25 prompt, as documented in the SDK for the [`DELETE_PACKAGE`]( 26 https://developer.android.com/reference/android/Manifest.permission.html#DELETE_PACKAGES) 27 permission. The only exceptions are the system package verifier app handling 28 [PACKAGE_NEEDS_VERIFICATION]( 29 https://developer.android.com/reference/android/content/Intent.html#ACTION_PACKAGE_NEEDS_VERIFICATION) 30 intent and the storage manager app handling [ACTION_MANAGE_STORAGE]( 31 https://developer.android.com/reference/android/os/storage/StorageManager.html#ACTION_MANAGE_STORAGE) 32 intent. 33 34 * [C-0-5] MUST have an activity that handles the 35 [`android.settings.MANAGE_UNKNOWN_APP_SOURCES`](http://developer.android.com/reference/android/provider/Settings.html#ACTION_MANAGE_UNKNOWN_APP_SOURCES) 36 intent. 37 38 * [C-0-6] MUST NOT install application packages from unknown 39 sources, unless the app that [requests the installation](https://developer.android.com/reference/android/content/Intent.html#ACTION_INSTALL_PACKAGE) 40 meets all the following requirements: 41 42 * It MUST declare the [`REQUEST_INSTALL_PACKAGES`](http://developer.android.com/reference/android/Manifest.permission.html#REQUEST_INSTALL_PACKAGES) 43 permission or have the `android:targetSdkVersion` set at 24 or lower. 44 * It MUST have been granted permission by the user to install apps from 45 unknown sources. 46 47 * SHOULD provide a user affordance to grant/revoke the permission to 48 install apps from unknown sources per application, but MAY choose to implement 49 this as a no-op and return `RESULT_CANCELED` for 50 [`startActivityForResult()`](http://developer.android.com/reference/android/app/Activity.html#startActivityForResult%28android.content.Intent, 51 int%29), 52 if the device implementation does not want to allow users to have this choice. 53 However, even in such cases, they SHOULD indicate to the user why there is no 54 such 55 choice presented. 56
