How would you go about updating the game when a patch drops?
On a computer it keeps your save files automatically so you can delete the game folder and still keep the saves.
On Android it's a bit more complicated, you have to keep the program installed and replace it in order to keep the saves. Otherwise you can find the save files and save them separately and copy them into the game folder for the new version, for which there are tutorials for Ren'Py online.