Kuo says that Apple will first release the 4.7-inch model featuring a 1334x750 326ppi display. That's the same aspect ratio as the current iPhone 5s. The 5.5-inch iPhone 6 will get a 1920x1080 screen at 401ppi, also the same aspect ratio.
The iPhone 6 is predicted to have a new A8 processor, 1GB of RAM, a bezel that is 10 to 20% narrower, a thickness of 6.5-7.0mm (iPhone 5s is 7.6mm thick), and a NFC chip. The camera will remain 8MP with a f2.2 aperture; however, optical image stabilization will improve image quality without increasing pixel count.
Kuo believes that shipments of the 4.7-inch iPhone 6 could reach 60 million units by the end of the year. The device will still be operable with one hand due to the narrower bezel and the side sleep/wake button. The 5.5-inch iPhone 6 is expected to reach nearly 9 million in sales by the end of the year; however, it could cannibalize sales of the iPad mini.
The 5.5-inch iPhone 6 is said to have a significantly larger battery with 50-70% more watt-hours than the iPhone 5s. Kuo also notes that only high-end iPhones such as the 64GB 5.5-inch iPhone 6 would have a sapphire glass display due to supply constraints. He says that Apple eventually plans to integrate Touch ID into the display and it needs sapphire glass displays to make that happen.
As expected, Apple will end production of the iPhone 4s and 4, and lower the price of the iPhone 5s and 5c to fill out the company's lineup.
More details on Apple's roadmap can be found here. Please follow iClarified on Twitter, Facebook, Google+, or RSS for updates.