Your Pixelbook is one of the few Chromebooks that can Android apps, with full Google Play Store access. Google pulled this off by running a version of Android within Chrome OS using containers.

Google updates this built-in Android for Chrome OS from time to time. I am hoping that Google will update the Android version within Chrome OS soon after a new version is launched. Not many devices get luck with such fast updates.

Keeping that in mind, I check the Android version on my Chromebook after each Chrome OS software update on my Pixelbook. Right now, we are at Android 7.1.1 Nougat. Android 8.0 is already available for a handful of devices, and Android 8.1 Developer Preview is also out. I will keep be regularly checking Android version, waiting for 8.0.

So, where do  I check this Android version on a Pixelbook? (or any Chromebook with Play Store access) Follow these instructions:

1. Open Settings app and go to Google Play Store section.
2. Click Manage Android Preference
3. A new Settings app launches. This is the Android Settings app.
4. The last entry on this page will be About Device. It should show the Android version.
5. Click About Device for additional information.

Hope this helps.