The Nexus 4 was officially released on November 13th, 2012. This LG-made smartphone was, at the time, the purest Android device on the market. The device has now been updated to Android 5.1, which is coming as an over-the-air update.
The Android 5.1 update is 174.5MB and brings the new quick settings menu, updated Device Protection feature that protects your data if your phone is stolen, and HD Voice features. In addition, Nexus 4 owners will see a slew of bug and several performance improvements that make your Nexus 4 a bit faster.
Read More: Nexus 4 Review
[source] Android Authority [/source]