With consumers eagerly awaiting the release of two new iPhones this week, the more dramatic change may be in the software, not the hardware.
The new mobile operating system called iOS 7 became available Wednesday, providing users of iPhones and iPads a bolder look, which may be a shock for some, but which Apple hopes will keep its fans happy and draw new customers.
"It is a major upgrade," said Gerry Purdy, analyst and consultant with Compass Intelligence who follows mobile technology.
"This is the first big thing that (Apple chief executive) Tim Cook has implemented, which puts all the software and hardware design under one roof, to have a unified experience across products."
While the new iPhone 5S and 5C, set to be released Friday, have received a lukewarm response, some analysts say the bolder statement from Apple comes in the new operating system, designed to keep people in the Apple "ecosystem."
The new operating system "has a different look, a different feel," said Ramon Llamas, analyst with the research firm IDC.
"People are going to have to rethink how they do things with their phone, and Apple is asking people to make a leap of faith."
With Apple seeking to regain traction in a mobile market dominated by the Google Android system, Llamas said iOS 7 will be a key test for Apple, because the new iPhones have failed to wow consumers.
"The feedback I'm getting is that people say (the new iPhones) are nice but they will wait for next year's model."
A small number of journalists who were allowed to review the new iPhone and iOS 7 underscored the dramatic change in the operating system.
"If you're coming brand new to iOS 7 and have been ignoring the Internet for the past three months, you're going to be in for a visual shock," wrote Darrell Etherington of the tech news site TechCrunch.
"The look is bound to be controversial; Apple has opted for bright, bold colors with more clean lines and far fewer textures, shadows and gradients. There is still some depth to the OS, however, with transparency effects giving a sense of background and foreground elements."
David Pogue of The New York Times said even with the iPhone launch, "the bigger news is iOS 7."
"The look of iOS 7 is sparse, white -- almost plain in spots. No more fake leather, fake woodgrain, fake green felt, fake yellow note paper," Pogue writes.
"The complete absence of graphic embellishments makes it especially utilitarian -- in both senses of the word. That's good, because whatever button or function you need is easier to find; it's bad, because, well, it can look a little boring."
Walt Mossberg at AllThingsD called the new operating system "a big improvement," adding: "The icons have been redesigned to be flatter and simpler, but they appear to float over your wallpaper, giving the effect of depth."
Apple says the new system has more than 200 new features, including improved multitasking, sharing, new camera apps, male and female voices for its Siri software, and the much-anticipated iTunes Radio.
The new software has drawn considerable attention even as the iPhone launch appears to be less spectacular than those in the past: Apple has said little about sellouts or delivery delays, and few expect the kinds of queues typical of iPhone debuts.
Purdy said that Apple may inadvertently hurt new iPhone sales by releasing the software upgrade for older models.
"It allows people with the iPhone 4 or 5 to get all the benefits of the Apple environment from a software standpoint, and therefore reduces the absolute need to upgrade the physical device," he told AFP.
The free upgrade helps Apple solidify its user base, the analyst said, even for those unwilling to buy a new device.
"It makes it attractive to stay in the walled garden of Apple," Purdy said, even without a revolutionary hardware change.
"This allows Apple to keep its users, though it may not change the direction of the Android ecosystem," Purdy added.
"But Apple isn't out to win market share. They want to produce the best products in the market and they're doing a good job at that."