Well I was unable to install the previous update Kraft-A6000-S040-150805 given by Lenovo and I got new notification for update Kraft-A6000-S052-150825. You can see in screenshot that it is upgrade from Android 4.4.4 to Android 5.0 and lock screen, wallpapers and themes will not be kept after this upgrade. You can update your lenovo a6000 to latest update Kraft-A6000-S052-150825 to get Android 5.0 (Lollipop). Previously it was running Kraft-A6000-S037-150605 which was Android 4.4.4.
You can get this update from System Update in your lenovo 6000 Android Phone.
