Ya I have done same thing on upgrade. I get same error when trying to register. I was however able to call Uconnect Customer Service through the Assist Icon. So even though Im not hooked to a antenna the call went through. I hung up before talking to them, just wanted to see if it would call out.
I actually called and spoke to Rep today, she first told me you can't put a 8.4 in a Jeep that has a 5.0. I laughed and said, "thats funny Im talking to you on one I already did" she was like, O really. I then proceeded to tell her how it was done and was curious if I can activate a Uconnect account to try some of the features. She said no, I then asked about OTA Updates that are coming, she told me that there is a new one that the dealer can do, I asked her it is the 16.13.13 update, she said ya thats the one, told her I already downloaded it and did update. To say the least they don't seem to be very knowledgable about the system they are supposed to be supporting. So will see what happens with the new OTA update.
2015 Cherokee Latitude 4x4 AD1
Jan 2015 Build
Xenon Depot 4300k HID Upgrade
LED Fog and Interior Lights Upgraded
Upgraded to 8.4AN
OEM Hitch and Bezel