Funny Thing Apple iPhone 4S became 4G after update.

Customers were astonished to see the 4G icon on the screen after the iOS updates. Apple has never launched a 4G device before the iPad. People don' know what algorithm is used by iOS to detect a 4G connection.

Please read the full details here.
http://www.slashgear.com/apple-iphone-4s-begins-showing-4g-icon-11217853/