There's no need, on PC save file is stored outside game folder, so just download new, unzip and play
On Android it's inside the game folder, and unless you have rooted phone, there's no access to save data, so just download new, unzip and install apk without uninstalling the previous version
No that is not normal, your save files should be available both he autosave on first slot or your manual save on any other slot, except you updated from 0.2.2.8, where save data wasn't compatible with the next and other updates and was removed
If ure on mobile then simply try to install the new version and it'll tell u that u already own the app and ask if u just want to update it, obviously click yes and nothing will be lost while the version updates
