Symptoms
After logging in to ReadyCLOUD after upgrading the ReadyNAS OS on your ReadyNAS system, you get a message about needing to upgrade firmware.
Cause
ReadyCLOUD now includes a number of major improvements, but these improvements require upgraded firmware on ReadyNAS systems. When you connect to ReadyCLOUD from your ReadyNAS system, ReadyCLOUD checks the firmware level. If the firmware is out of date, you see the following window:

Resolution
Click the Upgrade Now button to start the download and installation of the new firmware.
During the download you see a progress window similar to this:
Do not turn off your ReadyNAS system or try to use it until you see this window:
Click the OK button and continue to ReadyCLOUD.