The owners of the iPhone 4S who have upgraded their devices to iOS 5.1 may have seen an unexpected change in their device. All of a sudden, a 4G icon is appearing on the iPhone 4S, replacing the 3G icon. It sounds really strange since iPhone 4S does not support the 4G network. Hence it has created chaos among the users whether their iPhone 4S has been really changed into a 4G device. The answer is no, because the iPhone 4S will not support 4G network unless someone has inserted a LTE chip into it.
The secret behind the 4G icon has been solved now, clearing the confusion of the users. It indicates that it is AT&T's marketing strategy. The AT&T is promoting HSPA+ network as 4G. However a true 4G technology is not available in the market. But a couple of years ago, AT&T agreed that LTE and WiMax were considered as 4G, and the HSPA + network, which is the upgraded version of 3G technology, is to be considered as 3G.
Several changes took place in 2010 when T-Mobile USA started promoting its HSPA+ as 4G networks, since its performance was similar to the 4G WiMax and LTE. Later, AT&T upgraded its 3G HSPA to HSPA+. Gradually it started marketing HSPA+ as HSPA+ network 4G. Apple introduced the iPhone 4S which was not marketed as a 4G device since it did not want the customers to get confused with the network.
However Apple has changed the plans of 4G marketing. Thereby, the iPhone 4S that has been upgraded to iOS 5.1 will indicate the 4G network instead of 3G. It does not, however, mean that it supports the 4G network. It still continues to support the 3G network.