I have just installed Lightroom 6 and find I cannot download images from my Canon5DMark4 and get an error message that this RAW format is not supported. Do I need an upgrade, and how do I get that?
I know that Adobe added support for that model soon after it was released. Probably Lr 6.7 or so, back in Sept 2016, anyway.
If you installed from a disk image or installer that doesn't include the updates to current (6.8) you should be able to find an updater via the application (I'm guessing via the Help menu, then "Check for update..." or something). If you were using Lightroom 6.x via Adobe CC, then I don't think it would even be possible for you to have "just installed" an out-of-date version.
Anyway, I just wanted to give you some kind of response here before directing you to the proper forum for general Lightroom support. The Lightroom SDK forum is not frequented by very many people (and the topics in this forum are about creating plugins for Lightroom, i.e. geeky coder stuff. ;-) )
The general Lightroom support forum is here: