According to the KGI Securities analyst
Ming-Chi Kuo, Apple’s next generation iPhone 8 will feature a 5.8-inch screen
but only 5.15-inches of that will be main screen while the remaining space is
reserved for a Function area (Virtual Buttons).
Apple's next generation iPhone 8 will feature a 5.8-inch screen but only 5.15-inches of that will be main screen while the remaining space is reserved for a Function area (Virtual Buttons).

The most apparent change of the OLED iPhone will be a full-screen design, along
with the elimination of the Home button and current fingerprint recognition
technology. Of particular note is that we expect the OLED iPhone will adopt a
5.8” physical OLED panel. But the actual display area will be around 5.15”, and
the rest will be an area for functions (e.g. allocation of virtual buttons).

The 5.8-inch iPhone is expected to be similar in size to the current 4.7-inch
iPhone and will feature a bezel-less design to make the larger 5.8-inch display
possible. The function area will replace the Home button and Touch ID.

Via 9to5Mac