Factory images of Android 5.1.1 Lollipop have been released for the Nexus 7 (Wi-Fi), Nexus 7 2013 (Wi-Fi) and Nexus 10. This is just a minor update to fix bugs and add a few enhancements.
You can download the factory images for your Nexus device from Google Developers site. At present OTA update has just been made available for the Nexus 10. The Nexus 9 might jump ship directly to Android 5.1.1 from 5.0.1.
