Looks like all carriers are pushing Android 8.0 Oreo update for Pixel and Pixel XL devices. Earlier we saw Verizon has started rolling out Oreo update for Pixel devices, now AT&T is pushing the Oreo update to Pixel and Pixel XL.
The update is an OTA update, which should reach your device soon. If you haven’t received the update yet, you can check for it manually via the device settings. Go to Settings – About – Software updates.
Check out: Android Oreo 8.0 update: When will my device get it
The 8.0 Oreo update for Pixel devices weighs a good 950.7 MB and arrives as build number OPR6.170623.012. Of course, it brings along Oreo goodies such as picture-in-picture (PIP) mode, Notifications Visual Cleanup, Notification Badges, Always-On Display Updates, Instant Apps, and Autofill for apps.
Before you get all too excited for Oreo update, ensure that your Pixel handset is at least 50 percent charged and connected to a WiFi network to avoid extra data charges.
Source: Reddit