I could be wrong, but there should be drop down menu with which device you want to register
Thanks but I got it working. The High Flow Next with the not-expired update service was not connected when I started AQS. When I realized this I closed AQS, connected the High Flow Next, then restarted AQS. I still got the message that I need to extend the Update service. I thought maybe the Aquasuite Service also needed to be restarted so it would poll the devices again. I decided to just reboot, but even after rebooting, I still got the message. I rebooted again and the message finally vanished. I then updated to X.79 with no trouble. Now I understand why the message appeared, but I don't understand why it took 2 reboots for AQS to see that the High Flow Next's update service is still active.