Apple is expected to unveil iOS 7 at its Worldwide Developers Conference, or WWDC 2013, next month, but following rumors that said the Cupertino, Calif., company may delay the new mobile operating system due to its many alleged changes, sources close to Apple’s plans say the iOS 7 team is “borrowing” engineers from Apple’s Mac OS X team to finish the project on time.

One of the first to report the iOS 7 release date delay was Daring Fireball’s John Gruber, who said in a Branch chat with several Apple reporters in April that Apple was “running behind” with iOS 7 -- code-named Innsbruck -- which could impact its reported release date in June.

“What I've heard: iOS 7 is running behind, and engineers have been pulled from OS X 10.9 to work on it,” Gruber said. “Let me know if you’ve heard this song before.”

Gruber is referring to a similar occurrence in 2007, when Apple had to “borrow some key software engineering” resources from its Mac OS X team -- working on 10.5 Leopard at the time -- to work on Apple’s very first iPhone software.

In the Branch chat, FOX anchor Clayton Morris also said he'd heard "from engineers who've been moved off of their current 'nonprofit-generating projects' in order to work on the high priority software projects."

These earlier reports of an iOS 7 delay were confirmed with a couple of new reports this week from AllThingsD and the Loop. After AllThingsD’s John Paczkowski reported one Apple source saying, “Yes, yes -- it’s essentially a repeat of the iPhone/Leopard scenario.” The Loop’s renowned Apple journalist Jim Dalrymple confirmed the report with his signature one-word post: “yep.”

But while it may seem like a dire situation for Mac engineers to join the iOS 7 team, AllThingsD’s Apple source believes the doubling down on iOS 7 won’t affect its release date.

“Not as much of a fire drill,” the source said, again alluding to Apple’s 2007 iPhone/Leopard scenario. “It will ship on time.”

This last bit of news isn’t too surprising, given Steve Jobs’ famous motto: “Real artists ship.”

With the removal of iOS chief Scott Forstall in October, Apple’s lead designer, Sir Jony Ive, has stepped in to manage the “human interface” of iOS, as well as the company’s other hardware and software products. Most of what Ive has done with iOS 7 has reportedly involved removing the many skeuomorphic elements in iOS -- the ornamental metaphors that don’t serve any real purpose, like the faux-wood grain on the Newsstand app and the stitched leather in the Notepad app -- and replacing “flash” with “flat” and simple design choices.

According to one Apple source, iOS 7 is essentially iOS “de-glitzed.” Another Apple source called it a “much-needed ‘de-Forstallization.’”

“Put it this way,” one Apple source told AllThingsD. “You know Game Center’s green felt craps table? Well, goodbye, Circus Circus.”

According to alleged inside sources at Apple speaking to 9to5Mac, iOS 7 resembles the flat colors and shapes of Microsoft’s metro interface.

“While the look of the updated system may be surprising to some, iOS 7 is reportedly not more difficult to use than earlier versions of software platform,” Mark Gurman of 9to5Mac reported in April. “There is apparently no new learning curve in the same way there was no learning curve when the iPods went color. While iOS 7 does look different, its core apps and system fundamentals (like the Lock and Home screens) mostly operate in a similar fashion to how they do today.”

Apple has also reportedly redesigned the icons for all its first-party iOS apps in iOS 7, including Messages, App Store, Settings, Safari and others. IOS 7 will also reportedly release with “polarizing filters,” which decreases the chance that onlookers can see what you’re doing on your phone.

Apple needs to be careful about changing too much in iOS 7 -- changing a successful formula is definitely a risk -- but Apple CEO Tim Cook has a lot of faith in his lead designer.

“Jony, who I think has the best taste of anyone in the world and the best design skills, now has responsibility for the human interface,” Cook said in a Businessweek interview in December. “I mean, look at our products. [Cook reaches for his iPhone.] The face of this is the software, right? And the face of this iPad is the software. So it’s saying, Jony has done a remarkable job leading our hardware design, so let’s also have Jony responsible for the software and the look and feel of the software, not the underlying architecture and so forth, but the look and feel.”

Check out the 11 features we’d like to see in iOS 7, and let us know what you’d like to see in iOS 7 before its release date later this year.