Android 5.1 Lollipop is now official
Although Android One handsets loaded with Android 5.1 Lollipop have been around since last month, Google made this update official only two days ago. This means owners of supported devices should get the OTA update soon, while users of custom builds may have to wait a little longer. As usual, Nexus users are the first ones to get the update and Google already published links to factory images of this latest firmware release.
According to the official blog post that announces this update, Android 5.1 Lollipop "improves stability and performance and offers a few new features like support for multiple SIM cards, Device Protection and high definition (HD) voice on compatible phones."
Probably most important of these new features is Device Protection. It locks the lost/stolen device until the user signs up with the Google account. Resetting the device to factory settings does not disable Device Protection. This feature works on Nexus 6 and Nexus 9, as well as "on most Android phones and tablets shipped with Android 5.1."
Since some major carriers did not update popular devices to Lollipop yet, we might see some of them jump straight to 5.1. We will surely hear more about such updates in the coming months.