The official Summertime Saga Website is the recommended source for the latest stable and preview versions. For older versions like 0.20.15, you can find archives on Uptodown .
Once you've installed the game, here are a few essential tips and features to know: summertime saga version 0.20.15 apk download
Go to your Android settings, navigate to Security or Privacy, and enable "Install from Unknown Sources" to allow the APK file to install. The official Summertime Saga Website is the recommended