The Xperia Z4 smartphone isn’t exactly a secret, but now Sony has come out to officially announce the device in Japan. It’s basically the smartphone version of the Xperia Z4 tablet that was announced in March, and like that device, it doesn’t seem to be much of a visual overhaul compared to its predecessor. It does pack some pretty hefty upgrades on the inside, though, including an upgraded SoC and front-facing camera… expand full story