!WARNING!
When uninstalling old version on mobile, remember to plug in your phone to pc/laptop and make sure to copy your saves to not lose all progress. From my experience with android there is no possible way to open data directory on mobile. The only way is by using PC metod to enter that folder. After you plug your phone to PC use this directory on android to reach your saves: "your-phone\internal-memory\Android\data\MyBullyIsMyLover-Ch.1_Ep.2-android\game\saves"
Remember to copy whole folder "saves" and place it to your computer. Now safely uninstall the old version and install new one. After doing that, place "saves" folder in the same directory as before. I've messed up this once and since then I keep all my saves backuped.