The Android 5.1 Lollipop update for the Nexus 7 should be rolling out soon, as Google has posted the factory images for the Nexus 7 (3G) Android 5.1 Lollipop update on the Android Open Source Project page for Nexus devices.

Starting in March, Google began rolling out Android 5.1 Lollipop to its Nexus branded devices. The Nexus 6, Nexus 7 2012 Wi-Fi, Nexus 10, and Nexus 5 all began receiving the Android 5.1 Lollipop update. As we previously reported, the Nexus 5 Android 5.1 Lollipop update just began rolling out as well.

Android 5.1 Lollipop brings with it some significant changes and improvements over its predecessor, Android Lollipop 5.0. Among the changes are welcome improvements in battery life for devices running the new operating system, and increased protection and security afforded by a new locking system that prevents the device from being used when lost or stolen even, if it is given a factory reset. The device will still not work unless the original user signs in with his or her Google account credentials.

Another feature of Android 5.1 Lollipop is the ability to place high definition voice calls between devices that are running the new OS. Of course this feature is designed for smartphones and phablets as opposed to tablets like the Nexus 7.

Now that Google has posted the factory images for the Nexus 7, the rollout should be imminent. Although Google doesn't typically announce operating system rollouts in advance, users should check their devices for the new rollout coming soon.

The Nexus 9, Nexus 7 2013, Nexus 7 LTE, and Nexus 4 are still waiting to receive the new Android Lollipop 5.1 update, although it has been officially confirmed by Google, it is not yet clear whether those devices will be receiving the current 5.1 version of Lollipop that the Nexus 7 (3G) is receiving or a newer 5.1.1 version.