What exact version of Lightroom do you have right now? You cannot "buy" Lightroom Classic. It is part of the creative cloud program, and is only available by subscription. Lightroom Classic is installed locally on your computer, utilizes a local catalog, and stores images on your local hard Drive. There is no version of Lightroom that can be purchased anymore. Please explain what it is that you are now using, and what your intentions and future plans are.