The iPhone 5, not 4S, was Steve Jobs' last project with Apple.
Ashok Kumar, an analyst at Rodman & Renshaw, said in a research note that the iPhone 5 "was the last project that Steve Jobs was intimately involved with from concept to final design," CNET News reports.
Kumar said the phone will become a "cult classic," due to the emotional power brought about by the death of Apple's CEO Steve Jobs.
The iPhone 5 is expected to undergo a complete redesign.
"This is a very large project that Steve dedicated all of his time to. He was not that involved with the 4S because his time was limited," an anonymous source told CNET News.
Apple released the iPhone 4S on Friday and sold over 4 million copies over the weekend.
The 4S is aesthetically identical to its predecessor, but is loaded with new features.
One of those new features is Siri, a voice-command system built into the phone that responds to natural-language requests. The iPhone 4S also has the iCloud feature, which allows users to transfer iTunes music to all their devices.
Another new feature on the phone is a much-improved 8MP camera.
“For the iPhone 4S, we set our sights on competing not with other phones, but with point and shoot cameras," Apple Senior Vice President of Worldwide Product Marketing Phil Schiller said at a media event earlier this month.
"So we’ve added an 8 megapixel sensor that shoots 3264x2448 … we’ve also added backside illumination with a sensor that gathers 72 percent more light."
Schiller also said the iPhone 4S should offer CPU performance twice as fast the iPhone4, and has seven times faster graphics performance.
This 4S is the first model of the phone to be released since the death of CEO and co-founder Steve Jobs.
Apple has described the 4S as "the most amazing iPhone yet."