Google releases October security update for Pixels and Nexuses

If you own a Nexus or Pixel, you know what the first Monday of the month means: a new security update. It's no different this time around: right on schedule, Google has made the October security patches available to the devices it supports directly.
The factory images and full OTA zip files are up for grabs from the usual official website, catering to tinkerers. For normal people, the over-the-air rollout of the update is already underway.
As usual with Google rollouts, it's probably going to take a couple of weeks for all devices to receive the update notification. If you simply can't stand waiting, just go to Settings > System > System update and hit Check for update. This should immediately trigger the download (which is in the tens of megabytes range, nothing fancy).
The aforementioned path applies to Android 8.0 Oreo, if you're still on a Nexus 6 or Nexus 9, running 7.1.1 Nougat it will be slightly different - but if you're that desperate for security updates, you probably know exactly where to find the manual check option.
If you have a Pixel or Pixel XL, your build number after updating will be OPR1.170623.027 if you're in Canada or on Project Fi, and OPR3.170623.008 for everyone else. The Pixel C gets OPR1.170623.027, Nexus 6P has OPR5.170623.007, while the Nexus 5X is receiving OPR4.170623.009. The Verizon Nexus 6 has NGI77B as the build number, while other units get N6F27M. The Nexus 9 has two - N4F27P for the LTE model, and N9F27M for the Wi-Fi only iteration.