Which platform are you playing the game from? Android or Windows?
For windows, locate your game (The place where you put it) HHG->Game->Save, just simply drag the folder of it and drop it to the newer version and you're set
For Android you don't really need to do anything. Just install the latest version of the game and It will overwrite your current version but keep all your saved files so you won't lose it.
Have fun.