For every cool new thing Android Oreo brought to the table, Android 8.1 adds a bit of polish. After a brief but successful beta period, Google started rolling out the official 8.1 update to its Pixel and Nexus devices today, and it's everything Android 8.0 should have been.
The only eligible devices are the Nexus 5X, Nexus 6P, Pixel C, Pixel, Pixel XL, Pixel 2, Pixel 2 XL, and Nexus Player. Everyone else will have to wait. In the meantime, I'll explain how the update process will work and when you can expect to get it, then give you a rundown of the biggest new features and changes in Android 8.1 Oreo.
A new Oreo feature will let you get the 8.1 update as soon as it goes live — at least, in theory. Starting with Android 8.0, staged rollouts are a thing of the past. When you head to Settings –> System –> System Update and tap the "Check for updates" button, you'll immediately get the newest OTA update available to your device and carrier. However, carrier approval might throw a wrench in this for some users.
Android 8.1 has already passed Google's own approval process, but it's still pending approval from carriers like Verizon and Project Fi. This means that if you're using a SIM card from one of a handful of carriers, tapping that "Check for updates" button might not give you 8.1 just yet. If you're using an unlocked device and your carrier hasn't opted to test Google's firmware, however, you'll get the update right away.
If you don't want to wait, you can download Android 8.1 directly from Google, then flash the factory images using fastboot. 8.1 factory images aren't currently available for all devices, but download links should be available within a day or two.
8.1 is all about the finishing touches. For starters, there's a new power menu animation that slides out when you press and hold the power button. You'll also get an actual Android Oreo Easter egg in Settings –> System –> About phone, as well as other minor visual tweaks like a color-matched darkening effect when you open the notification tray and a Quick Settings menu that's now semi-transparent.
But the biggest changes include an automatic dark theme (for certain system menus only) and the ability to hide Oreo's "Running in the background" and "App draining battery" notifications. For folks concerned about the Pixel 2 XL's display, there are anti-burn-in measures and a saturated color profile. All in all, several key changes are in store, and you can read more about them at the following link.