First it was "coming soon", then it was due "in several weeks", and now it's finally here. We're talking about the first beta build of Android 8.0 Oreo for the Essential Phone. This has been quite some time in the making, with the company mentioning it back in September even.
The wait is over. If you head over to this page on Essential's website and enter your email, you'll be able to download a full OTA zip file for the beta Oreo update. You'll then need to sideload it onto your handset, a process which is explained, in a step by step fashion, on the download page. Although what you need to do is clearly outlined, this is definitely not something that people who aren't comfortable tinkering with their phones should attempt.
As this is a beta, bugs and various issues are to be expected too. Essential itself has already identified problems with Bluetooth stability and Android auto, so do proceed with caution. Hopefully all the kinks will be ironed out soon and a non-beta Oreo update will then be headed to every Essential Phone out there.