Essential Phone owners can now opt in to receive beta builds via an OTA, versus having to sideload the firmware. For some, this is a godsend since it eliminates the somewhat difficult process of sideloading in order to test the latest (in this case Oreo) goodness. User nobeconobe posted this in the Essential subreddit, so kudos to that person.
The process of signing up is quite simple. All you have to do is head over to Essential's site, select the Over-the-Air option, and fill in your information (the most important bit being your phone's serial number). Sideloading is still possible for those who like that route, but for the lazy or the ones who do not know how to sideload, this is a great option. I like this better than flashing the OnePlus betas in recovery mode, but both accomplish the same thing — Essential's method is just a bit more in line with Google's way.
A third option exists on the page, giving users the choice to go back to the stable channel. Similar to the OTA sign-up, enter your email address and device serial number, after which you'll presumably get an update on your phone to go back to stability. Hopefully, this means that you won't have to wipe unlike OnePlus' Open Beta program. The source link below is where you need to go in order to get started.