Your saves are stored separately from the game data so that you can keep your progress between versions. Just be sure that if you're playing on Android, you install the new APK over top of the old one rather than uninstalling it first - usually, this is fine, but some variants of Android will delete the save data when you uninstall. For the web version, saves are stored as cookies - so long as you don't go clearing your cookies, they'll stick around.