New schematics of iPhone 8 and iPhone 7s Plus leaked which revealed the accurate dimension of the devices. These schematics are used to mass produce the devices which are rumoured to be released to be released near the blackout days. Earlier molds of iPhone were leaked which was familiar to the schematics which got leaked recently.
Apple iPhone 8 dimensions are 143.4 x 70.77 x 7.51 mm which is excluding its dual-camera bump on the rear. It is bigger than the iPhone 7(138.3 x 67.1 x 7.1 mm ) but not as big as iPhone 7 Plus(158.2 x 77.9 x 7.3 mm). It rumoured that the device will have a 5.8 inch Oled display which could be possible, if the device will have smaller bezels. Which means the Apple will also join in the new bezel less trend. Fingerprint scanner is not visible on the schematics this could mean that it will be embedded under the front screen. There is a vertically mounted dual-camera setup in back.
As for the Apple iPhone 7s Plus dimensions are 158.38 x 78.1 mm which is similar to the iPhone 7 Plus(158.2 x 77.9 x 7.3 mm). As for the design there is no major changes made to the device as it will also have the horizontally placed rear-facing dual-camera setup.