For windows, from LW versions 4.4 & above the installer will initially uninstall the previous version (so long as it is version 4.4 & above), & then follow thru with the installation. But I would definitely not recommend keeping LW 4.8.1 with the idea that you will revert back. Doing so will result in corrupt downld preferences (as happened to me lol ) & your incomplete downlds would refuse to load. But you'll like the beta I'm sure!