Google has announced the immediate availability of Android 5.1 Lollipop for Nexus devices. Although the company isn't very specific about which devices will receive the update today, we can safely assume that all Nexus devices will be able to update.
What's interesting about Google's announcement is that there are a few new features that will be available once you update your operating system version to Android 5.1 Lollipop.
New features include support for multiple SIM cards, Device Protection, and support for high-definition (HD) voice on compatible mobile phones.
Basically, Android 5.1 Lollipop will now allow smartphones to use more than one SIM card when the device has multiple SIM slots.
The second major new feature coming in this update is Device Protection, which provides smartphone owners with an extra layer of security.
When stolen or lost, a device running Android 5.1 Lollipop will remain locked until the owner signs in with their Google account. This is true even if someone resets the device to factory settings.
According to Google, the device protection feature will be available on most Android smartphones and tablets that will be released "wearing" Android 5.1 Lollipop, except for the Nexus 6 and 9.
Additionally, Android 5.1 Lollipop brings HD voice calling to compatible devices, such as the Nexus 6 from T-Mobile and Verizon.
Last, and also important, is the ability to join Wi-Fi networks and control connected Bluetooth devices directly from Quick Settings.
Android 5.1 Lollipop for Nexus devices will be distributed OTA (over the air), gradually.
If you own one of the Nexus devices that is compatible with Android 5.1 Lollipop and you plan to upgrade with a factory image without waiting for the OTA distribution, you can find them on Google's developer website to download it.
How to flash the factory image on a Nexus device
First of all, download the correct system image for your Nexus device when it gets released by Google. Then, unzip it to a separate folder and connect your device to your computer via USB.
Boot the device into fastboot mode and, if necessary, unlock the device's bootloader. Open a terminal and navigate to the folder with the unzipped system image file to run the flash-all script, which will install the necessary bootloader, baseband firmware, and operating system.
