Sony releases Android 4.4.1 KitKat AOSP source for Xperia L
Note that these are the early days and some features will not work properly (Bluetooth and GPS), which makes it unsuitable for a daily driver to casual users. Still, this is a boon for custom ROM makers who are trying to bring the latest candy version ...
Xperia Z1s at the FCC, Android 4.3 update leaked for Xperia Z and ZL
Sony Xperia Z1 and Tablet Z getting Android 4.3 Jelly Bean from next month
Android 4.3 update for Sony Xperia Z and Xperia ZL is ready for download