You don't have to restart the game - you've never had to do that. The game automatically transfers save games between versions.
If you're on Win/Linux/Mac you just download, extract and play.
If you're on Android you just download, install over the top of the existing game and play.
The only time you lose your saves is when you delete the Android version, because both cloud saves and backup save locations are impossible due to the way Google does things.