Depends. On desktop its rather easy but on mobile its a little more difficult.
On desktop, my save from previous versions worked on newer versions, so i didn't have to do much. But when your save actually gets lost, you might want to look for the game in your %appdata% and make a backup of it.
On mobile its more difficult as you need an app that lets you enter hidden and blocked folders on your phone, or you need to connect it to your PC.