Author/Google Play Product Manager Dom Elliott

Since the launch of the Android App Bundle in May 2018, we have seen the developer community embrace this new publishing format and benefit from its simplified release management and advanced distribution features. There are now over a million official apps using the App Bundle, including most of the top 1,000 apps and games on Google Play. Examples include Adobe, Duolingo, Gameloft, Netflix, RedBus, Riafy, and Twitter.

In order to allow more users to experience these benefits, and to focus on promoting modern Android distribution technologies that benefit all developers, Google Play will begin requiring new apps to be released using the Android App Bundle starting in August 2021. This format will replace APK as the standard publishing format.

Modern Android application distribution

If you have not yet adopted App Bundle, this means that you are missing out on the following advantages:

  • Android App Bundle: Google Play uses App Bundle to generate and optimize APKs for distribution for different device configurations and languages. This approach results in smaller applications (on average, 15% smaller than a typical APK) and faster downloads, which in turn leads to more installation and less uninstallation.
  • Play App Signing: Distribution as an App Bundle requires Play App Signing, which uses Google’s security infrastructure to avoid App signing key loss and can be upgraded to a new App signing key with stronger encryption.
  • Play Feature Delivery: More than 10% of the popular apps using App bundles are using Play Feature Delivery to customize which functional modules to deliver to which device and when. It supports three modes of delivery-on-installation, delivery-on-condition and delivery-on-demand.
  • Play Asset Delivery: Dynamic Delivery of large resources reduces user wait times while reducing Delivery costs. Games using Play Asset Delivery can use the texture compression format as a Delivery condition so that users only get the resources appropriate for their device and avoid wasting space or bandwidth.
  • Future Improvements: Play App Signature will soon begin rolling out APK Signature Scheme V4 to suitable applications, allowing them access to upcoming performance features on newer devices. Check out the Google Game Developers Summit on July 12 for more details.

Review: Relevant changes from August 2021

Publish type

Substituted object

Compliance is required by August 2021
New Google Play apps APK Android App Bundle (AAB)
Extended file (OBB) Play Asset Delivery 或  Play Feature Delivery
Updates to existing applications There is no change
New installation-free experience Free to install application ZIP To enable theFree Android App Bundle (AAB)
Install-free updates

Note that the App Bundle requirement only applies to new apps, while existing apps and private apps for specific Google Play users do not currently have to comply with this requirement. Thanks to the many developers who have contributed to the development of the App Bundle, and we look forward to bringing more updates to developers in the future.

Answers to some common questions about Android App Bundle

Q: How much work does it take to develop an App using an App Bundle compared to APK?

For most applications, building an AAB file instead of an APK file requires only a small amount of work. The key is to choose other options at build time and test in the usual way. App Bundle is an open source format supported by major build tools, including Android Studio, Gradle, Bazel, Buck, Cocos Creator, Unity, Unreal Engine, and others. With the Play Core native SDK, the Play Core Java SDK, and the Play Core Kotlin SDK, users can easily start using the optional advanced App Bundle features regardless of their preferred coding environment.

Q: Why doesn’t App Bundle support extended files (OBBs)? Why should Play Asset Delivery be used?

APK requires a separate file (OBB) to push more resources to the user. However, because the OBB does not have a signature and is stored in the application’s external storage, it is not secure enough. With Play Asset Delivery (PAD), users can replace the OBB by publishing games larger than 150MB as a single App Bundle in the Play Store. In addition to a smoother release process and a more flexible push model, the Pad has many advantages over previous extended files: incremental patches of its resources are optimized for larger applications, meaning that updates require much less device storage than OBB. As a result, its quick-follow installation mode improves installation rates and store conversions. Finally, since ASTC now supports about 80% of devices, the positioning conditions of the texture compression format allow you to push ASTC to devices that support this feature. You can locate many Android devices while efficiently utilizing available hardware and device storage space.

Q: If I use App Bundle, can I continue to publish through multiple distribution channels/App stores?

Sure, you can do it in a number of ways. You can use a common app signing key or use a unique app signing key for different channels, including the unique app signing key for Google Play. You can build and sign artifacts locally for all distribution channels, or download distributable APKs from Google Play and deploy them to other channels. APKs downloaded from Google Play, regardless of whether they are downloaded through the App Bundle Explorer in the Play Administration Center or the Play Developer API, are signed by the same key managed by the Play application signature.

Q: If I want to release a new application, can I determine the content of my application signature key?

Yes, we will provide this option in the PLAY administration center. When you create a new application, you can choose to provide Google with the application signing key. This allows you to locally retain a copy of your app’s signature key, for example by creating a version of your app that is signed with the same secret key as Play and distributing it on other channels. Soon, the Play Administration Center will make it easier for you to first launch your app, as long as you can change your app signing key before your first release to the open channel.

Q: When distributing on Google Play, how do I ensure that my app is delivered to users in the way I prefer?

You can download and inspect artifacts at any time using the App Bundle Explorer in the Play Store or the Play Administration Center, and validate the application through the Play Developer API. Additionally, the App Bundle’s code transparency is an optional new feature to check if the code running on the device is the code that was originally built and signed by the developer.

Q: If I have already published an app on Google Play, can I start using Play app signing without providing a copy of my existing app signing key?

To use the Play app signature, you need to provide a copy of the app signature key, because Google Play needs to use this signed copy to sign and provide version updates to your existing users. This distribution format works for most developers, and over a million apps use the Play app signature in the official release. We will soon offer an additional option for existing apps that will allow developers to perform key upgrades to opt-in to signing the Play app. This option means that the Play application signature can use the new unique key for the new installation and subsequent updates. However, to do this, when you upload the App Bundle, you also need to upload the original APK signed with the old key, so that Google Play can continue to push updates to existing users.

Q: Can I change my application signature key?

Of course, some apps can request an app signature key upgrade for a newly installed app in the Play admin center. Google Play will use the new key to sign new installed apps and app updates, and the old app signing key to sign updates made by users who installed apps before the key upgrade. Soon, the Play app Signature key upgrade will also add support for APK Signature Scheme V3 key rotation. This will enable more applications to opt for key upgrades, allowing applications signed with the upgrade key to reach more users.