User blog comment:Superslacker87/Three Different Versions/@comment-5110407-20120812000912/@comment-49697-20120815212323

You can't go back. I experimented once on my other game flip-flopping back and forth between the Google Play version and the Amazon version. Once the server registers as running a newer version, that's it. When I went back to the Play version, it told me I needed to update the game in order to play.