The iPhone 6, with a bigger screen, could be priced at $299 under a contract, $100 more than what Apple charges for the iPhone 5s. Federico Ciccarese

The release date of the future iPhone 6 has been the subject of much speculation since last September’s release, the iPhone 5s, turned out to be an incremental update. Some industry analysts have suggested dates as early as June. But a recent report from the Japanese newspaper Nikkei claims that the iPhone 6 will launch “as early as September,” an estimate that is in line with the release dates of the last three iPhone models.

The report also states that the iPhone will come in two different sizes, a rumor that has turned up in more than one place. The next iPhone is speculated to come in a 4.7-inch display size and a larger 5.5-inch display. The iPhone market has been notoriously small -- in size that is. The increase of screen size is possibly a move to compete with a growing phablet market outside the United States. Ben Bajarin of Creative Strategies suggested at Macworld 2014 that a larger iPhone would do well in emerging markets where smartphone devices are often the only computers that consumers have.

But a conflicting report came out of Barron’s, after UBS analyst Steve Milunovich checked into the supply chain. He determined that the smaller of the two sizes “seems certain,” but the larger of the two “may or may not launch at the same time.”

Whether the iPhone 6 is one or two sizes may be unclear, but Nikkei claims that other innovations are pending. “Manufacturers have apparently begun making such components as fingerprint sensors and chips for liquid-crystal drivers,” the report states. It goes on to say that “mass production of liquid crystal display panels” will begin production next month, directly inline with a September release.

The iPhone 6 is also rumored to get a sapphire screen instead of Gorilla Glass. A recent patent application seems to corroborate that claim, and Tim Cook, Apple’s CEO, confirmed to ABC News that the manufacturing plant in Mesa, Ariz., is producing sapphire crystal substrate. However, Cook didn’t mention either the iPhone 6 or the highly anticipated Apple wearable, the iWatch.

The iPhone 6 will most likely run on a faster A8 chip produced by TSMC and Apple competitor Samsung. The screen will be a high-resolution Retina display, somewhere between the current 326ppi and 401ppi. It is also suggested that the screen will continue to be LTPS, the current iPhone screen technology, instead of the iPad screen technology IGZO. LTPS offers better electron mobility, making it a faster screen for consumers.