to function. If you are using this device for daily tasks, experts generally recommend upgrading to a device running at least Android 6.0 (Marshmallow) or higher for basic security. Are you trying to update a specific phone model
For devices running older versions (4.4 KitKat or 5.0), jumping to 5.1.1 feels like getting a new phone. android 5.1 1 update download
If you must install this version for legacy purposes, you can check for the official update on your device via: Android 5.1 Lollipop Review: Improvements and Changes to function
The 5.1.1 update was primarily a maintenance release focused on "under-the-hood" stability rather than new visual overhauls. android 5.1 1 update download
to update to its last compatible version for better app support: Play Store (three lines) > Play Store Version