Tech site This Is My Next has obtained a leaked image of an internal AT&T memo that says that says that the carrier is working with Apple to update the network indicator for AT&T's iPhone 4S to read '4G.' The memo, in full, reads:

AT&T is working with Apple to update the network indicator for AT&T's iPhone 4S to read 4G. This will happen with an iOS release from Apple. Since iPhone 4S is an HSPA+ device, our customers will get 4G speeds from day one. Only AT&T has this unique network advantage.

It's a bizarre move that doesn't seem to gibe with Apple's previous reluctance to call its latest product a 4G phone. At Apple's Let's Talk iPhone event on Tuesday, it seemed as though the handset maker was intentionally sidestepping the issue of the iPhone's true network designation. This latest development would seem to indicate that Apple is conceding to pressure from AT&T to bite the bullet and actually call the iPhone 4S a 4G phone.

In fact, the protocol the iPhone 4S is using for data transfer is High-Speed-Downlink Packet Access, or HSDPA, which is not, strictly speaking, a 4G but a 3GPP technology. However, using HSDPA will allow the iPhone 4S to reach download speeds comparable to other mobile phones designated as 4G.

Additionally, the incorporation of HSDPA constitutes one half of the software upgrade required to outfit a phone with HSPA, the most widely used mobile broadband technology - the other half being adoption of High Speed Uplink Packet Access (HSUPA). A further upgrade allows HSPA to work more efficiently, qualifying it as HSPA+ which is a dyed-in-the-wool 4G technology. Since devices only require the capacity for this upgrade to be designated as HSPA+, the iPhone 4S is, technically a 4G device.

AT&T and T-Mobile have both adopted HSPA+ networks, with AT&T also offering LTE, another true 4G technology. With upgraded systems that do offer faster download speeds, it's understandable that Apple and AT&T would be averse to sticking with a 3G designation for the iPhone 4S. However, as This is My Next points out, this is a curious move given that AT&T is currently trying to get its LTE network off the ground. While many carriers do some fast talking when it comes to their network designations, AT&T is likely to face more scrutiny than others, since it is likely that AT&T-iPhone 4S customers will be confused by the 4G designation when they do not have access to LTE.

There is some question as to when AT&T and Apple will implement the change. It will require an iOS update from Apple, though the memo asserts that [AT&T's] customers will get 4G speeds from day one. Most likely, the update will not be released before the first round of pre-ordered phones arrives, giving customers enough time to scratch their heads over the change.