A new firmware update for Sony’s flagship Xperia Z2 has started to roll with build number 17.1.2.A.0.314. The update keeps the phone on Android 4.4.2 KitKat, so Xperia Z2 owners have to wait a bit longer for Android 4.4.4. According to the Xperia Update Checker, the generic firmware is available for the D6503 LTE variant of the Xperia Z2 in Thailand, Russia, Kuwait and Korea.
No noticeable changes have been seen in this update, it does not include the apps to SD card feature that appeared in the Xperia T2 Ultra KitKat firmware. At the moment it appears that there is no way to root this firmware, so you may want to hold fire on updating right now. If you want to give it a try you can download the FlashTool FTF firmware from here.