How to update your app in Google Play
IMPORTANT NOTE: Since you're not signing the app yourself, you should not enroll your app in Google Play App Signing.
This article describes the process of updating an existing app in Google Play. If this article doesn't answer all of your questions, please reference Google Play's Updates article for further information.
Increment your Version
Every time you build your Andromo app, its 'version code' is incremented. Google Play uses this value to determine whether it's a new build of your app. This however differs from the version string. The version string is what you and your users will see to identify the version of the app. While it isn't technically required, we strongly suggest increasing your application's version number each time you release your app. For example, increment your version from 1.0.0.0 to 1.0.0.1.
You can adjust this setting on the "App Info" tab of your Andromo project's settings. After updating the version, build your app again and download the new Android Package file (APK) that represents your updated application.
Upload your New APK
IMPORTANT NOTE: Since you're not signing the app yourself, you should not enroll your app in Google Play App Signing.
Once your Andromo app is ready to be published, login to your Google Play Developer Console. Select your app from the list, and then select the "APK" tab along the left-hand side. You can upload your new APK file using the "Upload new APK to Production" button. You can then either save those changes, or publish your new file.
Update the Store Listing
The next step is to let your users know what has changed since the last version of your application, such as bug fixes or new features. This information can be entered in the "Recent changes" area of your store listing, for example: 1.0.0.1 - Fixed an issue....
You can read about the recent changes section in the Recent Changes topic of the Google Play for Developers Help.
Once you're finished making changes to your listing, make sure to click the "Save and Publish" button to update your app in the store.
How Updates Work
Once your app has been updated in the Developer Console, it will take a while for the changes to become visible in the store, so be patient. Wait at least 24 hours before contacting Google Play support. It will also take some time for your users to be notified that an update is available. Users will see an update available notification for your app, or if they have automatic updates enabled, your app will be automatically updated for them, and they'll be notified of the change.
Note: Update notifications are controlled by users on their device, so users that have chosen not to receive notifications will not be notified of the app update.