Play App Signing by Google Play is required to publish with Android App Bundles, which is the recommended publishing format. Google Play will start requiring new apps to be published with the Android App Bundle starting August 2021. Refer: https://android-developers.googleblog.com/2021/06/the-future-of-android-app-bundles-is.html
To be able to use Play App Signing with Appflow, you can follow the steps below:
For new apps:
First, create a new app in the Google Play Console. In order to enable app signing, you'll need to navigate to the new release screen, on one of the Production, Open testing, closed testing, or internal testing pages.
Select the Create new release button as seen below (it doesn't matter which release type, since you don't have to actually go through with creating a new release right now):
Under the App integrity section, click the Change app signing key button:
Select the Export and upload a key from Java Keystore option. This is the only way in which you can retain the key and have Google Play use it for signing. If you're using Appflow to build Android apps in the cloud, this is also the required option so you can upload the keystore to Appflow.
Follow the instructions on the screen to generate the Keystore and you can use the same Keystore file to sign your app in the Appflow dashboard as well. If you need any help generating the Keystore file you can refer to our docs here.
Once the generated zip file has been uploaded, you're all set! Build an AAB binary signed with the keystore file then upload it to Google Play.
To upload the Keystore file to appflow refer to our docs here on how to create a signing certificate in appflow.
For existing apps:
As of now, no changes are required for updates to existing apps, but if you would like to use the AAB format, you can enroll for the Play App signing as seen below:
This is for an existing app that was published using self-signed APKs. In this case, because the app was previously released already, app signing can be enabled and configured on the App Integrity page here in the left nav.
To opt into app signing, you'll need to upload your own app signing key. Not just any key, but It has to be the one that was used to sign previous releases of the app. You can use any of the two methods as seen below. Once upload the key, you should be able to enroll into the Play App Signing with the provided instructions. If you are facing any further issues, please contact Appflow support for further assistance.