The current software is V21e and can be downloaded via LG's proprietary Mobile Software Updater, as shown above. Reports are just starting to trickle in, but we do know the update is 178MB and brings GRI40, or Android 2.3.3. Before downloading and installing the update, you should know that it will break root. Other than that... well, we don't know a whole lot yet, but we'll update if we hear any more major details.
Open GApps can now optionally install Google Assistant
[Update: May enable Google Assistant on non-Pixels] Google App v6.13 "alpha" appears with support for Payments on Google Assistant, and prepares enhanced Offline Search, Lite Mode, Recent page, and much more [APK Teardown + Download]
Android 7.1.2 Beta finally hits the Nexus 6P, but fingerprint gesture support is missing