If rumors are to be believed, Apple is poised to release a 4-inch phone some time in the first half of 2016. It will purportedly resemble an upgraded iPhone 5s, Ming-Chi Kuo, analyst at KGI Securities, said in a report published at MacRumors.

"As there is still demand for a 4-inch iPhone, we believe Apple will upgrade this product line," Kuo said. "We predict Apple will mass-produce this new 4-inch iPhone in 1H16 with metal casings. In order to make the current iOS 9 or next-generation iOS 10 run smoothly, Apple may adopt an A9 chip for this new phone."

While the 4-inch device will be equipped with the chip that currently powers the iPhone 6s and 6s Plus, it will be sold without Apple's new 3D Touch technology in order to differentiate the new product line. There is no available information as to the name of the new device, except that it will probably fall under the budget segment. In addition, the phone will supposedly not follow the concept behind the plastic and colorful iPhone 5c, according to The Verge.

Once it is released, the 4-inch iPhone could directly compete with the Sony Xperia Compact product line, which dominates the small-sized phone segment today.

Many expect that the rumored 4-inch device will be unveiled next year. This is attributed to how KGI Securities' reports have been largely accurate in the past, according to Apple Insider. Kuo, for example, correctly anticipated the 4.7 and 5.5-inch iPhones as well as the complete 6s spec sheet.