The company announced the news via its official blog post and also noted that the update is now rolling out for the three devices, though as usual, the timing and availability of the update for the Xperia Z1, Xperia Z1 Compact and Xperia Z Ultra will vary by market and mobile carrier.
In addition, the company also announced that the Android 4.4 KitKat update for Sony Xperia Z, Xperia ZL, Xperia ZR and Xperia Tablet Z will be rolled out in mid-Q2 2014. Further, Sony also revealed plans to roll out the Android 4.4 KitKat update for Xperia T2 Ultra, Xperia E1 and Xperia M2 soon.
Sony revealed the changelog for the Android 4.4 KitKat update for the Sony Xperia Z1, Xperia Z1 Compact and Xperia Z Ultra. Some of the changes included are performance and UI optimisation; tweaked Status Bar and Quick Settings that according to the company are more intuitive and customisable; and the new Xperia Themes, which are downloadable UI packs from Sony Select.
The Japanese handset giant has also announced the revamped Sony native app portfolio which includes Messaging, MyXperia, Smart Connect, Small apps, TrackID, TrackID TV, Sony Select, and Smart Social Camera among others.
Sony's media apps such as Walkman, Album and Movies, are now integrated with Sony Entertainment Network cloud service. Sony has also added a sleek launch animation and live wallpaper, which is reminiscent of the Sony PlayStation 4, across the lock and home screens.
The blog post said, "We've been working to build new Sony experiences on Google's KitKat release to create some neat / sweet features (if we say so ourselves) - in addition to a few performance tweaks here & there."