https://www.theverge.com/2017/11/14/16652532/essential-phone-google-android-oreo-beta-access-update

Android phone maker Essential is the latest manufacturer to open beta access to Android Oreo for its namesake smartphone. The company says eager participants can go download the latest Android OS refresh from its website by heading over to its developer portal. You don’t need to be a registered mobile developer; any interested Essential owner can put Oreo on their device so long as they’re comfortable using beta software that still may suffer the occasional bug.

Essential is just the latest Android smartphone brand to start rolling out Oreo, which launched back in August but remains installed on just 0.3 percent of all Android devices. The Sony Xperia XZ1 line shipped with Oreo preinstalled, as did Google’s most recent Pixel 2 devices. (Google’s older Pixel and Nexus devices also have the software.) However, other Android manufacturers like Samsung, HTC, and Huawei are just now pushing out beta releases alongside Essential.