Of all rumours floating around about the new iPhone 5, this one has the most traction – a bigger retina display likely around 4 inches and a form factor of 16:9.

Application developers initially expressed concern that iPhone was going to go the Android way with increased fragmentation and multiple versions of apps will be needed  to work well across different screen sizes and resolutions. But analysts from the Taiwanese firm KGI Research have indicated that the horizontal resolution will continue to be 640p, which means that unmodified apps will just be centered automatically leaving a couple of black strips of unused screen on either side.

KGI Analyst Mingchi Kuo says

“If developers don’t want to adapt software for iPhone 5, the App can still successfully show on the screen except for the blackened areas on two flanks [...] If developers decide they want to make the necessary amendments to make things look good, the cost will be kept to a minimum thanks to the same old horizontal resolution.”

Further,

“a larger iPhone 5 will have a different screen resolution, but the same horizontal resolution of 640 [pixels] as iPhone 4S will help minimize development cost.”