Apple has run its newest mobile operating system, iOS 8, through the gamut of beta testing and developer feedback, and the time is nigh for the California tech giant to release its final test version of the software ahead of a public release.

Rumors have surfaced on the Christian Post that Apple will release the public version of iOS 8 on Sept. 10, the day after the company is expected to unveil its iPhone 6.

Before the public version is released, Apple -- if it sticks to tradition -- will release a GM version of the software sometime before Sept. 10. No date for that release has been disclosed and rumors are far-ranging.

But developers that have gotten a good look at iOS 8 claim that it will be vastly different than its predecessor and those developers have quite a task ahead of them to catch up with iOS. ZD Net pointed out specific challenges facing developers ahead of iOS public debut.

More than any system before it, iOS 8 increases customization and flexibility of the software. Andrew Levy, CEO of app performance management firm Crittercism, said that iOS 8 has at least 4,000 new application programing interfaces, or APIs.

An API is a set of routines, protocols and tools for building software applications, according to Webopedia. The API specifies how software components should interact and are used when programming graphical user interface components.

The new iOS will rely much more heavily on the cloud than previous versions, meaning that not only will users be more demanding on cloud reliability, developers will need to think about optimizing performance.

Apple has included both HomeKit and HealthKit in iOS 8, the latter of which can measure a litany of health-related metrics. Having these on the operating system will require iOS 8 to seamlessly connect to more devices than ever

The above issues will challenge developers upon the release of iOS 8 -- historical data suggests that some 60 percent of devices pick up the newest system within a few weeks of its release -- meaning they will have to react fast to stay ahead of the curve.