The iOS 5.1 update, "4G", AT&T, and the 3G Toggle
by Brian Klug on 3/7/2012 AnandTech
When the iPhone 4S first launched, AT&T ominously noted (through a document leaked to The Verge) that it was "working with Apple" to update the 3G indicator to 4G in the status bar. Back then, the extent of just how much AT&T was working with Apple on a regular basis to both build carrier.ipcc bundles and beyond was unknown, but the two have worked together in the past to make UI related changes, going all the way back to the iPhone 3G's signal to bars mapping. In addition, obviously the carrier works with Apple to both validate baseband behavior and respective updates. However, having the carrier dictate changes to UI seemed like new territory.
With respect to the iPhone 4S there was also some confusion about whether the device was HSPA+, and whether that met ITU-R's earlier 4G definitions. All of that we addressed in another post that I'd encourage you to take a look at as a primer for all this. I'm not going to go into that whole debate again since honestly the "4G" thing boils down to a matter of definition, and whether or not you subscribe to ITU-R or not is a matter of principle.