Oreo isn't a gigantic update. Its most conspicuous improvements are a prioritized approach to notifications (and notification dots for app icons), picture-in-picture video, a redesigned Google "feed" and new emoji. Many of the big improvements are under the hood, such as a framework that separates third-party software from Android's core and should streamline future OS upgrades.
Still, this gets the ball rolling on Oreo's adoption beyond Pixel and Nexus devices. Just 0.3 percent of active Android devices are running Google's latest and greatest as of this writing, which is lower than the percentage of people using Gingerbread -- a version released in 2010. While HTC isn't going to be as influential in expanding Oreo's adoption as heavyweight rivals like Samsung, LG or Huawei, it could represent an important nudge in the right direction.
Source : https://www.engadget.com/2017/11/27/htc-u11-android-oreo-upgrade/