I've noticed the IOS auto-upgrade functionality when the IOS software release 12.4(15)T was launched, but it was missing from the 1800 images, so I wrote a note in the "to-test" folder and forgot about it. In the meantime, the code obviously appeared in IOS images, as Joe Harris managed to get the auto-ugprade from CCO to work. However, the IOS documentation lacks "a few" details, while Joe's post has a step-by-step explanation.
Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.