You can optionally apply "What's new" text to the uploaded APK(s), in order to inform your user of changes contained in the new app version.

You add entries for as many or as few of your supported language as you wish, but each language must already have been added to your app, under the "Store Listing" section in the Google Play Developer Console.

The language must match the language code shown in the Developer Console, e.g. "en-GB" for British English, or "ar" for Arabic.

The text may be between zero and 500 characters.

For more information on describing what's new in your app, see the Google Play documentation:
https://support.google.com/googleplay/android-developer/answer/189724


Both fields support substituting environment variables in the form ${SOME_VARIABLE} or $SOME_VARIABLE at build time.