While the still-unannounced iPhone 7 has been said to greatly resemble Apple's current iPhone 6s models, its successor will reportedly harken back to iPhones of the (technologically) distant past. The phone, apparently due in 2017, may sport a glass exterior, according to KGI analyst Ming-Chi Kuo.
According MacRumors, Kuo says that this change will arrive at the same time that Apple is adopting a new type of display for the iPhone:
"Apple already uses glass casing for iPhone 4/ 4S, and non-Apple brands have also been using glass casings. We therefore think a drop test will not be problematic for glass casing. A glass casing may be slightly heavier than an aluminum one of the same thickness, but the difference is so small that the use of the thinner and lighter AMOLED panel will compensate for that."
This note comes after a report last month, also from Kuo, which claimed that Apple would release a 5.8-inch phone with a curved display and curved glass body.
Remember, the 2017 flagship iPhone is likely at least 17 months away at this point, and even if Apple does have plans like this, they could still change. Despite Kuo's past accuracy, it's wise to take these reports with a grain of salt.