The Xiaomi Mi A1 is undoubtedly one of the best budget phones you can buy right now, as long as you live somewhere where it is sold.

It's Xiaomi's first Android One device, meaning it runs completely stock Android with no modifications. Xiaomi promised that it would receive Oreo by the end of 2017, and while the final update still isn't ready, some owners have been invited to a private beta test.
Indian news site Telecomtalk had a chance to test the private beta, and reports that several updates have already gone out over the course of testing. All the usual Oreo improvements are present, like the redesigned Settings app, adaptive icons, Picture-in-Picture, and the Autofill API. The site reported that app load times are much quicker, and animations are more smooth.
The Oreo update also adds quick charging support to the A1. I'm unable to verify if the charger included with the A1 supports quick charging (I had to send my review unit back), so you may have to buy a new adapter/cable to take advantage of the faster speeds.
Xiaomi is still promising that the update will be ready by the end of 2017, so unless it is delayed, it should be released within the next six days.

http://www.akelicious.com/2017/12/android-80-oreo-in-beta-testing-for.html