I need to buy an old version of Lightroom for my old computer. I know that the 5.7 works (downloaded the testing version) and now i would like to make it permanent but I couldn't find it on the website.
Adobe only sells LR6 or subscriptions to LR CC 2015. But you may be able for find a boxed version of LR5 still available at on-line stores. Simply use the serial number from inside the box to validate the download you have already installed.