Have the 2015.3 release with camera raw 9.3. Apparently I need camera raw 9.8 to recognize my new Panasonic Lumix DMC-FZ2500. How do I upgrade to that?
You cannot update Lightroom with the Camera Raw plug-in. That plug-in is for Photoshop. The only way to update Lightroom is to update Lightroom itself because all of that technology is part of the Lightroom program. Unless you are running a very old operating system you should have upgraded to Lightroom Classic CC and you should be running version 7.4. The version you are running is significantly old. Is there a specific reason you are running that old of a version of Lightroom?
Just as a point of clarification, are you paying a subscription fee for the Creative Cloud photography plan?