I actually realized something that works easily if you have your previous save in your system. It's worked with every RenPy game I've played. What you do is:
Step 1: Open the old version's folder, and enter the "game" folder.
Step 2: Copy the "saves" folder in the old version's "game" folder.
Step 3: Open the new version's "game" folder.
Step 4: Paste the "saves" folder into the new version's "game" folder.
Only on Android is it necessary to copy save files.
On other platforms the save/ -folder contains copies of the save files that are store elsewhere. On Windows it is %APPDATA%, on Linux ~/.renpy/Harem\ Hotel-<random-number>/, on Mac something similar that I do not remember. All versions of game use that same place.
Installing new version of game to a new directory and loading save file from old version should just work.
