Sony recently announced that Xperia Z2 and Z3 will soon be receiving the upgrade for Android 5.1.1 Lollipop.
Sony Xperia Z2 and Xperia Z3 are confirmed to get the OTA update by July-end, according to Xperia Blog.
The Android 5.1.1 Lollipop update will bring a lot of improvements in these devices. In addition, it must be noted that the Android Lollipop 5.1.1 upgrade will apply to only those devices which are not rooted or modified. In case the user is using a modified phone, the upgrade will not be rolled out for their device, according to The International Business Times.
This firm ware is certified under PTRCB 23.4.A.0.546, which means that it will not be the same for all devices. Moreover, since this is an "over the air" upgrade, different users will receive it at different times. It will be released in stages and is rumored to be commence from Japan.
In the scenario when this roll out will be declared as a success, it will trickle down to other Sony Xperia devices as well. It is also highly probable that the lower end Xperia devices will also get this firm ware upgrade soon.
In order to install the Android Lollipop 5.1.1 update, the device must be connected to a Wi-Fi connection, or else the upgrade will not kickstart.
To look for the upgrade, the users can go to Settings-> About device -> Updates -> Check for updates. In case the device is eligible for an update, the user will be asked to download the file and run it.