As the iPhone 5 release date nears, there has reportedy been an significant decline in the sales of the iPhone 4S as customers prepare to wait for the next generation device from Apple.

The iPhone 4S experienced one of the most successful launches of any smartphone in history despite not being a complete revamp of the iPhone 4's design. The iPhone 4S was released back in October but sales have now been hit due to the increasingly frantic rumors surrounding the iPhone 5 release date, as well as the hugely successful launch of the rival leading smartphone from Samsung, the Samsung Galaxy S3.

A note to clients from Goldman Sachs' Bill Shope has said, "While multiple quarters of sequential declines in iPhone units would normally be expected to pressure Apple's stock, we suspect the window for the bears is limited by the imminent iPhone 5 product cycle and already prudent near-term investor expectations," according to Market Watch.

In the most recent "leaks" surrounding the iPhone 5, specifications for the device include 1GB of RAM, integrated 4G LTE radios, and NFC (near-field-communications) hardware. The features have been touted by BGR, which also stated that the device will be released either at the end of September or early October.

According to reports Apple is also employing new screen technology for its next-generation iPhone that will make it considerably thinner. A thinner screen, it is said, will yield a thinner device overall.

However, there have been contradicting reports over whether the iPhone 5 has already gone into production. Previous rumors had stated the device was already in its production stage, however, a new report by BGR has said otherwise.

Apple puts its devices through various stages before a product is manufactured, including an "engineering verification test" stage and the "design verification test" phase, according to the BGR.

The site believes, according to its sources, that the iPhone is currently in the first of those stages.

For the Verizon iPhone 4, that device went into the first "engineering verification test" in mid-November 2010, and did not make it to the second "design verification test" until December. Even then the phone was not released on the carrier until February 2011.