The iPhone SE launched some debate over phone size, but the Apple iPhone 7 will be exempt from it – measurements from a schematic show the new model will match the size of the 4.7″ iPhone 6s down to a tenth of a millimeter.
On the diagram, the 7 measures 138.30 x 67.12mm. The thickness is not given, but the 6s is 7.1mm – Apple’s thinnest phone yet, but not its thinnest device (the iPod Touch is 6.1mm).
The 3.5mm audio jack appears to be safe, but that was never an issue for thickness (as the iPod shows). For the sake of the battery, we’d be okay if Apple kept the 7.1mm thickness of the iPhone 7 (or better yet, make it a bit thicker).
Source (in French)