Apple reportedly has three different phones in development, but people ultimately want to know about the true successor to the iPhone 5. What could Apple's next-generation high-end smartphone look like, feel like or do?

In just the first month of 2013, we've heard dozens of varying reports about this next-gen iPhone -- unofficially labeled as iPhone 5S or iPhone 6 -- speculating on its various features and how it could truly differentiate itself from all previous iPhones.

We've rounded up some of the most likely iPhone 5S or 6 features, and, while everything on this list must be deemed a rumor -- Apple refuses to comment on speculation about its future products -- many of the features on this list do have backing from analysts with excellent track records and sources from within Apple's supply chain.

Without further ado, here's what we've heard:

1. Improved rear camera: Last week, iLounge Editor-in-Chief Jeremy Horwitz released a series of reports on the next-gen iPhone, which he calls iPhone 5S. In addition to a processor bump (an all-new A7 system-on-a-chip), Horwitz believes the next iPhone will feature a better camera system.

“The iPhone 5S is still months away from mass production, but our source suspects that the star feature will be an upgraded rear camera -- perhaps featuring Sony’s 13-Megapixel sensor, plus the aforementioned flash upgrade,” Horwitz said. “Current prototypes are codenamed N51 and N53, with July mentioned as the target date.”

Giving credence to these rumors, KGI Securities analyst Ming-Chi Kuo -- one of the best at the business at predicting Apple’s product pipeline -- also believes the iPhone 5S or 6 will feature a new-and-improved camera system, including f2.0 aperture on the rear side and a "smart LED flash" for enhanced photo-taking.

2. Fingerprint sensor: While a sharper camera is all fine and dandy, one particularly strong rumor we've heard is that the iPhone 5S or 6 will finally show some love for the home button, which is said to include an integrated fingerprint sensor to replace the need for usernames and passwords on the phone.

A fingerprint sensor makes great logical sense to be an iPhone 5S or 6 feature: Unlike other rival smartphones with multiple buttons the bottom, the iPhone has only one mechanical button on its face, which makes it exceedingly easy and intuitive for users to find and use this feature. Furthermore, given Apple’s urgency to acquire Florida-based AuthenTec last July (as noted in the company’s own filing to the SEC), there’s an excellent chance that we’ll see this unique feature in the iPhone 5S or 6 when it releases later this year.

3. Photographer's timer: Traditionally, self-timing cameras are used to take pictures of a big group or a self-portrait. But in Apple's self-timer, a patent granted March 8, the iDevice's camera can identify the photographer and ask if they want to be in the picture. At that point, the iPhone will simply wait until it detects the photographer's face in the viewfinder before it automatically snaps a photo.

"But what about interruptions? What happens if I get a call after I set the self-timer?" Wonder no more. If you set the timer and then your phone goes off, the timer will still wait until it has detected, recognized and verified that you are the photographer and that you're in place for the photo.

If anyone can pull off this kind of intelligent face recognition in photo-taking, it's Apple: The company purchased Polar Rose, a Swedish software firm that specializes in facial recognition, back in September 2010.

4. 3-D photography: As an increasing number of people are relying on their smartphone as their camera, Apple might be the first major phone maker to release a phone that can take 3-D photographs.

While existing 3-D cameras and video recorders gather three-dimensional information from objects, they're generally incapable of getting detailed enough information in relation to the shapes, surfaces and depth of the objects. Apple's patented solution involves a series of systems, tools and methods to capture a 3-D image by using multiple sensors and cameras. One sensor would capture a polarizing image, while two other sensors would capture two different nonpolarizing images, and Apple's system would combine the images into a composite. If Apple is putting a great deal of focus into the camera, it's possible Apple might throw in a couple of extra sensors on the rear side to pull off unique three-dimensional photographs.

5. IGZO display: Apple has reportedly invested a great deal of time, energy and money into display technology, likely to be used for its next-gen iPad and iPhone, including this year's iPhone 5S or 6.

A Jan. 3 report released by the China Times said Apple might switch to a Touch On Display panel currently in development at Taiwan-based Innolux Corp., which has reportedly been licensed to use Sharp's proprietary IGZO display technology.

Whether or not Apple chooses Innolux to make the next iPhone's screens, however, Apple is most likely going to feature Sharp's ultra-thin IGZO display technology in its next iPhone.

In late December, DigiTimes and Apple analyst Horace Dediu both mentioned Apple’s alleged investment in the ultra-thin IGZO displays produced by Sharp, predicting the inclusion of the technology in Apple’s next batch of iOS devices, including iPhones and iPads. Dediu also pointed to Apple’s recent $2.3 billion investment in “product tooling, manufacturing process equipment and infrastructure,” believing the cash was used to help bail out Sharp, which had been in financial straits in 2012. Sharp is reportedly going “all in” on IGZO technology, so it’s possible Apple saved Sharp to leverage its investment in the next generation of displays.

IGZO display technology is not only thin and tough, but it can even handle higher screen densities than Apple’s Retina display, which is visually stunning on its own. IGZO displays can reportedly handle display densities north of 330 ppi; for a quick comparison, the new iPad 4 can only achieve 264 ppi.

One of the advantages of IGZO display technology is its lower power consumption. Most Apple products, from the iPhone 5 to the iPad 4, require cartoonishly big batteries to achieve just eight hours of power -- this is because current-gen Retina displays are extremely power-hungry. If Apple wanted its iPhone 6 to not only last longer during the day but also charge faster when plugged in, IGZO seems to be the way to go for the next generation of iOS devices.

What features do you think Apple should include in the iPhone 5S or 6? Let us know in the comments section at the bottom of the page.