Lightroom versions 1 through 6 were sold under a perpetual license. A user paid a one-time fee to own the software indefinitely. Updates (e.g., 6.0 to 6.1) were provided free of charge to license holders to fix bugs and add camera support.
To understand the context of the version 6.1 download request, one must understand the shift in software licensing models. adobe lightroom version 6.1 free download for mac os
It belongs to the perpetual license era. Lightroom versions 1 through 6 were sold under