Google started rolling out updates today for Android 5.1.1 to a number of different Nexus devices today, with factory images getting posted as well as OTA download links being posted for those who want to flash and install the new software manually to their devices instead of waiting for it come over-the-air. Earlier we saw software drops for the Nexus 4, Nexus 5, and the Nexus 9 in both WiFi-only and LTE models. Very recently, Google also posted up the factory images for both the original Nexus 7 cellular model from 2012 and the newer 2013 Nexus 7 LTE model, making the Nexus 6 the very last supported Nexus device which is stuck on Android 5.1.
While we recommend anyone who has never installed software manually before to simply wait for the updates to come through over the air, if you want to proceed with the manual install you can find a handy guide here to help walk you through the process of flashing the Nexus factory images to your device. You can also find the correct factory image download links for both the 2012 Nexus 7 mobile model and the 2013 Nexus 7 LTE model below.