Owners of the Xperia T, TX, and V had a little hope before today that their beloved devices would see some of that KitKat goodness, but now their hopes lay dashed to bits at the feet of Sony's heartless engineers. These devices won't be making the jump to Android 4.4 KitKat, but will continue to live on with Android 4.3 Jelly Bean.
Despite not updating these devices, you have to give Sony credit for being up-front about its software versions and update plans. Each phone has its own product page with up-to-date version information and a chart that shows what Android versions it has gone through and what is expected to come later. This chart used to show "Under Investigation Android 4.4 (KitKat)" for all three devices, but now it says Android 4.3 is the "Latest and final version." Sad.
All three devices were launched with Android 4.0 Ice Cream Sandwich, so they've gotten a fair amount of attention over the years. They're also (as you can tell from the launch OS version) getting a bit old, and none of them were flagship devices to begin with. This outcome is rather expected in that context.