With shots of a new Sony smartphone surfacing ahead of a possible reveal at next month's Mobile World Congress, we guessed it wouldn't be long until we laid eyes on the software powering it. XperiaBlog got its hands on an Android 4.4.2 KitKat build for the Xperia D6503 (rumored codename Sirius), providing us with an overview of the new UI and a list of possible features coming to Sony's next Android flagship. The headline-grabbing tweaks include options to record 4K and high frame-rate video, utilize Smart backlight controls (similar to Samsung's Smart stay feature), two home launchers for better accessibility, advanced call handling options and a new built-in answering machine. Head over to XperiaBlog for the complete lowdown on the KitKat-centric features expected to make their debut in Sony's Z1 successor and possibly other high-end handsets in the Xperia range.