Following rumors, Xperia Z4 is carrying a 5.5-inch 2560X1440 display, 4 GB RAM, 16 GB in-built memory, a Snapdragon 810 CPU, Adreno 430 GPU as well as NFC, wireless charging, IP68 certified – dust proof and water resistant functions.
From this picture, you can easily assess the differences between the Xperia Z3 and Xperia Z4 LCD Touch Digitizer. The proximity sensor and front facing camera have exchanged their positions, and the Xperia Z4’s earpiece speaker position has been raised to the top edge. What about the bottom of the phone?
Obviously, the Xperia Z4 has removed the stereo loudspeaker position compared with the Xperia Z3. Rumored that Xperia Z4 will still come with dual loudspeakers; perhaps the Xperia Z4 has placed the loudspeakers to the bottom edge side to the USB charging port.
However, all above information is based on rumors. For exact informations, we need to wait for the official announcement from Sony or release of product.