OnePlus 3 and 3T users in the Open Beta Program have received an update that finally gives them a taste of Android 8.0.0 Oreo. It's but a beta update, of course, so it comes with a slew of bugs and worries.
https://www.notebookcheck.net/Last-gen-OnePlus-devices-get-first-taste-of-Oreo.258264.0.html