Sony has confirmed that the Android 5.1.1 update for the Xperia Z2 and Z3 series devices, which was certified just a couple of days ago, will be rolling out later this month. The confirmation came from the Japanese subsidiary of the company
The changes that the update will bring include additional Wi-Fi and Bluetooth options in the notification menu and new icons for the settings menu. You can also expect the update to deliver new animations.
The change-log that the company has released contains changes from Android 4.4.4 KitKat to Android 5.1.1 Lollipop, which means that most of what it lists won't be new given that the devices are already running Android 5.0.2.
My wifi is not working properly after this update 5.1.1
just upgrade , or migrate