LR6 can upgrade an LR5 catalog, but LR5 cannot open a catalog from LR6.
So there is no backwards compatibility.
You may upgrade to LR CC from LR 5 and you may keep both the Applications on your Computer.
Also the catalog that you create in LR 5 is compatible with LR CC , but the catalog created in LR CC will not be compatible with the previous version , that is LR 5
You can have both on your computer and run both (one at a time). But LR 5 cannot use a LR 6 catalogue, and vice versa. If you try to open a LR 5 catalogue with LR 6, Lightroom will copy the 5 catalogue and convert the copy to the 6 format. The conversion is one way: LR 5 cannot do anything with a LR 6 catalogue.
I doubt that you'll be able to do what you seem to have in mind. Any chance you can convince the company to make a version for CC on PC?
Thank you everyone! I just wanted to confirm that LR5 would not be deleted automatically upon install of LR6. Unfortunately the owners of RPG Keys looked into it and though they were able to update for Mac, Windows seemed like something they were not willing to invest more time into because they were running into issues. Makes me think that the owners are not that interested in continuing the software which is disappointing. I have looked into other options, but haven't found the right fit for me on Windows 10 yet. I can't get Paddy to work on Win 10 and that software appears to be dead in the water as well. Kind of slim pickings at this point other than Motibodo PRO Skin Kit for Lightroom | Motibodo but there are some things about that system that I am not crazy about. Pusher Labs — Workflow Solutions for Lightroom looks like a pretty awesome solution but it is Mac only. http://www.slrlounge.com/3-modular-lightroom-controllers-suit-post-processing-needs/ discusses some other options that are springing up but I am not sold on. I would love to hear from others that may have more suggestions.