Sony Xperia Z1 during it's world premier at the IFA consumer electronics fair, 2013
Sony Corp's President and Chief Executive Officer Kazuo Hirai presents a new Sony Xperia Z1 smartphone during it's world premier at the IFA consumer electronics fair in Berlin, September 4, 2013.Reuters

Sony's flagship models Xperia Z1 and its smaller variant, Xperia Z1 Compact and the phablet have begun receiving the latest Android KitKat update.

Company announced the news via official Sony Mobile Blog;  It said that new Kitkat update comes with custom Xperia Themes (more than 280 styles) and Sony exclusive feature enhancements like Sony WALKMAN, Album, Movies applications, PlayStation 4 compatibility (as well as same sleek launch animation and livewallpaper across the lock and home screens), and uplifting of Sony's entire native app portfolio to the latest versions - like bringing tweaked / improved / current experiences for  Messaging, MyXperia, Smart Connect, Small apps, TrackID, TrackID TV, Sony Select, Smart Social Camera and more

To check for updates:

Go to Settings >>About phone >> Build number / version; 

Since the update is rolled out in phased manner, timing & availability will vary by market & carrier. 

Apart from Sony's exclusive feature improvements,  KitKat software is said to bring in enhancements like visually appealing white status bar, improved battery performance, Caller ID security, Emoji characters to enrich texting experience, wireless printing (with select HP printers) and more.

Apart from these three devices, Sony has confirmed to release the new KitKat update to Xperia Z, ZL, ZR smartphone and Xperia Tablet Z in Q2, 2014.

Newly launched smarphones Xperia T2 Ultra, Xperia E2 and M2 are also slated recieve the new chocolate-wafer flavored Android software soon, but the specific time line will be annouced later, said the company.

Key Features of Android v4.4 KitKat OS Update:

Location Menu: This integrated location menu enable users to easily activate GPS, Wi-Fi and mobile networks, while simultaneously keeping a tab on the battery consumption by the location service based apps.

Enhanced Google Mobile Service (GMS) Apps: This application helps user to automatically back-up photos and video clips. He/she also can create, view, share or rename Google Docs and files.

Improved Caller-ID: If a user receives a call from unknown number, the phone will look for matches on the net with local listings via Google Maps.

Priority Contacts: The new OS empowers the phone to automatically prioritize contact list for easy access, based on the frequency of the peoples' contacts to which users talk.

Immersive Display: To enhance the entertainment factor, the new OS comes with immersive mode, where the status bar and navigation buttons disappear in to the background while you play music, games and read e-books. Users can just swipe the edge of the screen to bring back the utility buttons.

Enhanced Message Grouping: Google has brought in some improvements to the new Hangouts app; now, users can find all their text SMSs and MMSs, audio and video call details all at one place. He/she can also share location and send animated GIFs.

Emoji Characters:  Initially users had to install third party app to use colorful characters in their SMS. Now, with KitKat update, the keypad comes pre-loaded with native Japanese Emoji emotion icons.

NFC and Wireless Printing: Google's new OS comes with a new Quickoffice app where-in people can create and store word documents in cloud storage as well as print files wirelessly on NFC-enabled HP printers.

Multi-tasking:  With efficient memory management, users can multi-task by opening multiple applications; Listen to music while you can browse through the Internet.  

Performance: Like all software updates, the new KitKat enhances smartphone's performance as well as efficient RAM management, leading to increase in battery.