Sony has begun rolling out Android 5.1.1 Lollipop update to the Xperia Z1, Z1 Compact, and the Z Ultra in some regions. The new lollipop update patches stagefright vulnerability, improves performance, makes the camera focus faster alongwith new bluetooth/Wifi options in the notification tray.
With the new update some enterprise features have also been activated like instant sharing of calendar events, calendar agenda in email alongwith the ability to use the Sony Smartwatch 3 as a shutter for your Xperia device.
Given that these are quite old devices, its good to see Sony still sending out updates and patches to these smartphones. Once you apply the update, the build number will bump up to 14.6.A.0.368. Do tell us your experience after installing the update in the comments below.
Source: Xperia Blog
