After Google announced that they would be rolling out the beta for Android 7.1.2 in the next few days, the rollout has now started. After seeing the factory images appear on Google's developer website, the search giant has begun pushing out the OTA to compatible devices that are enrolled in the Android Beta Program. These compatible devices include the Nexus 5X, Nexus 6P, Nexus Player, Pixel C, Pixel and Pixel XL devices. The download weighs in at a pretty hefty 827.9MB. So you'll definitely want to be on WiFi before downloading this update and installing it on your device.
Those that do download and start using this beta version of Android, keep in mind that this is indeed a beta version and that it will be filled with a few bugs and other issues. So it may not be a good idea to use this version of Android on your daily driver. This is the first beta for Google's promised quarterly updates. It is going to bring some changes to your device, but not as many as Nougat did when it first arrived on your smartphone a few months ago. This is part of Google looking to keep everyone happy with new features and changes to their device, instead of just updating Android once a year. Although many believe that this will make fragmentation an even bigger deal.
Now the update to the Pixel and Pixel XL will be slightly different than those with the Nexus 5X, Nexus 6P, Nexus Player and the Pixel C, and that's largely due to the fact that the Pixel and Pixel XL both have features that are exclusive to those devices, like the Google Assistant, which is still very much in beta form right now. It's unclear when the Google Assistant will make its way to other devices right now, but it likely won't be with this update. Google will be pushing out a few more beta's of Android 7.1.2 before the final version rolls out to devices in the next month or two. It's unclear which devices will get updated, but we do know that the Nexus 6 and Nexus 9 won't be seeing Android 7.1.2.