Changing google-services.json file, Do I have to release new build apk to market?

  1. SDK Version:40
  2. Platforms(Android/iOS/web/all):Android

Changed firebase account, so does google-services.json file. but nothing else…

So I wonder how to publish it to prod? new apk ? or simply publish to release channel?

Yes you have to, because this file is built with gradle at buildtime