Why does Google Play use AAB instead of APK? The official explanation is here

On June 29, Google officially announced that will begin to require new applications to be released using the Android App Bundle from August 2021. This format will replace APK as the standard release format.

Why did Google choose to replace the traditional Android application package file format APK with Android App Bundle (AAB)? Is AAB unique? In this regard, Google Play product manager Dom Elliott gave a detailed introduction.

The Android App Bundle format was released in May 2018, and its advantage is to make application files smaller and save storage space. Google said that since the release of AAB, the developer community has actively embraced this new release format and has benefited from its simplified release management and advanced distribution features. Currently, there are more than one million official versions of apps using the AAB format, and most of the top 1,000 apps and games on Google Play are listed here, such as Adobe, Duolingo, Gameloft, Netflix, redBus, Riafy, and Twitter.

So why use AAB format instead of APK? Google said that this move aims to allow more users to experience the advantages of AAB and promote modern Android distribution technology that is beneficial to all developers.

Next, let’s take a look at the advantages of the AAB format and what impact this new rule will have on Google Play apps.

AAB: Modern Android application distribution technology

The AAB format has the following four advantages:

• Android App Bundle: Google Play uses App Bundle to generate and optimize APKs for distribution to different device configurations and languages. This method can make the application smaller (15% smaller than the average APK on average), faster download speed, thereby increasing the amount of installation and reducing the amount of uninstallation.
• Play application signature: The distribution of the App Bundle requires the Play application signature. This signature uses Google’s security infrastructure avoid the loss of the application signing key , and can be upgraded to a new, more encrypted application signing key.
• Play Feature Delivery: More than 10% of popular applications that use AAB are using Play Feature Delivery. Through it, users can which function modules will be delivered to which equipment, and when to deliver . Play Feature Delivery supports three modes: delivery at installation, delivery on condition and delivery on demand.
• Play Asset Delivery: Delivering large assets in a dynamic manner can reduce user waiting time while reducing delivery costs. Games that use Play Asset Delivery can use texture compression format as a delivery condition, so that users can only obtain resources suitable for their device and avoid wasting space or bandwidth.

In addition, the Play application signature will launch APK Signature Scheme v4 to suitable applications in the near future, allowing them to access the upcoming performance features on newer devices.

From August, what changes will the new AAB rules bring?

After one month, all new Google Play apps will have to be published using AAB. After the Android APK became popular for many years, this change is not trivial. So what impact will the implementation of this rule have on Google Play apps?

As shown in the above table, new Google Play apps will use the AAB format instead of APK, but this rule will not affect the update of existing apps. In terms of the free installation experience, Google Play will enable the free installation AAB to replace the free installation application ZIP.

Google stated that AAB's requirements only apply to new applications, and that existing applications and private applications for specific Google Play users do not currently need to comply with this requirement.

Reference link:
https://mp.weixin.qq.com/s/9DFf-uGQY3KJNMwwyAlhkA
https://android-developers.googleblog.com/2021/06/the-future-of-android-app-bundles-is.html