By the looks of it they havent downloaded the hotfixes at school. Can’t you just ask them to update 4.20.0 to 4.20.3? Those are just fixes and dont have additional content so it wont affect them in any negative way anyway. You can’t revert hotfixes afaik so the only other option that comes to mind is to get a copy of the engine from school, uninstall yours at home and try to get it working, which wont be as smooth as it sounds. :\
Actually i forgot the source code option: https://github.com/EpicGames/UnrealEngine/releases/tag/4.20.0-release