After tomorrow, Apple will hold a special event with full coverage of the MacMagazine in which most likely to present the new “iPhones 6s / 6s Plus” (among other things). But, believe it or not, rumors about the iPhone 7.
According to the (normally) well-informed analyst Ming-Chi Kuo, from KGI Securities, for the 2016 generation of its smartphone, Apple intends to go for an even thinner design than the current one, bringing the iPhone closer to the iPod touch, in terms of thickness. The iPhone 6 is 6.9mm and the iPhone 6 Plus is 7.1mm, while the iPod touch is only 6.1mm.
This very small thickness of the iPhone 6, added to its smooth aluminum housing, makes it difficult to use it with just one hand nowadays if you don't use a case. I speak from my own experience: after years without using an iPhone case, since I got the 6, I prefer it with the official Apple case (leather).
It is worth remembering that the rumors about the “iPhones 6s / 6s Plus” indicate that they will gain about 0.2mm in thickness, mainly due to the incorporation of Force Touch technology. It is a very small difference (practically imperceptible, I would say), but it must be taking Jony Ive's sleep.