Apple iPhone trade-ins are hitting new highs as customers rid themselves of older models for a larger iPhone 6 -- a device that could be announced in two weeks if one leak is correct.

According to NextWorth, a company that buys iPhones for cash, the iPhone 6 should shatter previous records. The iPhone 4s sold around 4 million units in its first weekend in 2011, while the iPhone 5 sold around 5 million units in its first 2012 weekend. Apple did sell 9 million units of the iPhone 5s and iPhone 5c in the first weekend of 2013, but NextWorth thinks Apple can reach the 10 million mark with the release of the iPhone 6.

Analysts and Apple expect the iPhone 6 to shatter previous records thanks to pent up anticipation for a larger-screen iPhone. Android phones passed the 5-inch mark a long time ago, but Apple's iPhones have never had displays larger than 4 inches. Apple is expected to release two iPhone 6 models this year: a 5.5-inch model and a smaller 4.7-inch variant.

"There's tremendous pent-up demand for a larger-screen iPhone. We've seen a lift of about 350% from the baseline this week. That's up from a lift of 182% last year, or almost two times the acceleration," said Jeff Trachsel, chief marketing officer at NextWorth.

It shouldn't be much longer until the pundits are proven either right or wrong. A new leak has surfaced thanks to well-known French Apple blog nowhereelse.fr. The blog's editor, Steve Hemmerstoffer, claims to have gotten his hands on a picture showcasing an iPhone 6 box with the date Tuesday, Sept. 9.

The date has been thrown around before, and many were initially inclined to believe the validity of the leak given Hemmerstoffer's track record, but a few discrepancies create some doubt.

As MacRumors points out:

"The '10' date actually corresponds to the date when iOS 7 debuted, Monday, June 10. Therefore, the iPhone 5s card did not depict the phone's debut date, which means an actual Apple quick start card for the iPhone 6 would be unlikely to display 'September 9' over the iOS default date."

"Additionally, the design of the card also lacks slashes between the Ring/Silent switch and Home Button/Touch ID sensor, and the font of the time is not quite in line with Apple's style. Nowhereelse.Fr claims that Apple has opted for a more simple insert design that does not show the actual device to explain its difference from the iPhone 5s insert, but it is unclear whether that is factual. Even when poised as a possible rough draft for a finished quick start guide, the glaring errors on the card continue suggest that it is indeed a fake and not representative of the actual insert card that will be included with the finished iPhone 6."

As usual, Apple has been silent on the matter, although it's pretty much given the Cupertino giant will release new iPhones in September. Invites to the unveiling should hit the press soon.

You can find out more about what specs and features the iPhone 6 will most likely sport in our roundup.

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