Android 5.0 Lollipop was made official a few days ago. As is the norm, Nexus devices are the first ones to receive the official update. Google has started to roll out the OTA update for the Nexus devices. Not all the devices have received the update yet. Google usually performs this operation in batches. If you are feeling too impatient, then you can install Android 5.0 on Nexus 5, using Google uploaded factory image. Follow the guide given below.