You don't need to do anything - new versions work with old save files unless otherwise noted and they are stored in the same place. If you want to make a backup anyway the save files are located in %localappdata%/Circadian_Dice
(Oh, and if you use the itch.io client to run the game your game is patched with new updates automatically - no manual downloads needed.)
Happy to hear that you're enjoying the game! :)