Easy installation without "clear data".
1. Uninstall the official app.
2. Re-install the official application.
3. Recover your Dokkan account with Google.
4. When it's done, press "ok" and CLOSE THE APP on the main screen which searches for downloads.
5. Uninstall the official app.
6. Install the modded app.
7. Recover your account with Google.
8. Well done!