Back in the beginning of May owners of the Xiaomi Mi Box who signed up for beta testing of Oreo on their devices got the update straight from Android Marshmallow. Now regular users also have started receiving a notification that their new software has arrived.
Screengrabs of the incoming update
Xiaomi Mi Box jumps from Android 6.0.1 straight to Android 8.0. It now offers a new homescreen launcher of Android TV that gives content channels more visibility, instead of apps. During setup, there are now recommended apps and minor interface changes, plus the usual performance tweaks. The whole package comes in at 615.8 MB.
All owners of the Mi Box should be getting the update now, but if somehow you didnt get a notification, head to About -> System Update to see if the Oreo version has arrived.