$ add system image http://dl.ubnt.com/firmwares/edgemax/v1.6.0/ER-e200.v1.6.0rc3.4715473.tar
Version [v1.6.0rc1.4709697.141009.1954] is about to be replaced
Are you sure you want to replace old version? (Yes/No) [Yes]: y
Trying to get upgrade file from http://dl.ubnt.com/firmwares/edgemax/v1.6.0/ER-e200.v1.6.0rc3.4715473.tar
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 70.0M  100 70.0M    0     0  9359k      0  0:00:07  0:00:07 --:--:--  9.7M
Download suceeded
Checking upgrade image...Done
Preparing to upgrade...Done
Copying upgrade image...
Removing old image...Done
Checking upgrade image...Done
Copying config data...Done
Finishing upgrade...Done
Upgrade completed