After the LG Optimus G and the Verizon Galaxy Nexus, now it's the Sony Xperia Z turn to get the unofficial Android 4.4 KitKat ROM treatment. that's the first of the 2013 flagship crop to get a KitKat ROM, if we don't count the Nexus 5, of course...
Source: http://www.phonearena.com/news/Sony-Xperia-Z-gets-the-Android-4.4-KitKat-treatment-in-a-stable-ROM-release_id49063
Source: http://www.phonearena.com/news/Sony-Xperia-Z-gets-the-Android-4.4-KitKat-treatment-in-a-stable-ROM-release_id49063