If you have a valid serial number for Lightroom 5, you technically own the software. However, Adobe has removed the official download links for older versions from their main servers to push users toward the Creative Cloud subscription.
Users in the Adobe Community often share legacy links. While Adobe has taken many down, some direct links to their servers still occasionally work, though they are often 404 or redirected to current trials. Direct Download Link. Mac 5.7.1: Direct Download Link. lightroom 5.7 update download
