I worked with Josh Larson at RiverPark in October 2018 because I was getting the same message about the maps being over 1 year old. At that time I had updated my SW to v4.57.4546.1617 (same version that you just installed). I don't know if I should be surprised that you got your coach less than a year ago and it didn't have the version of software that was released at least 14 months earlier.
After upgrading, I was still getting the error about the maps being over 1 year old. Josh had me delete a timestamp file from the SD card and that restarted the 1 year clock on the current maps.
You can fix that by just deleting the tag file manually. To do this open the card with Finder (or your file manager) so you can see the files on it. Click on the Navi folder, then the Bin folder, and find the file Navi.cfg, go ahead and delete this. Next time you put it into the radio it will create a new one and the message will not display again until next year.
My NAV is once again showing that my maps were over a year old. I tried updating, but I was already up to date (no SW or map update in the past two years??). Once again, I deleted the timestamp file and the error message went away.
I do wonder to what extend the system is being supported. I prefer my Garmin 780 over the Xcite system. I usually plug my destination into both of them and if I need to make a stop along the way (fuel, lunch at a rest area), I plug that into the Xcite system.
