The Shenzhen-based company OnePlus typically announces the Android Beta preview before the final update. Just a few days back. the company announced Android Oreo beta for OnePlus 3 and OnePlus 3T so many could test Android Oreo before Public roll-out.
But, what about their latest flagship OnePlus 5? Well, OnePlus's Co-founder Carl Pei on his twitter handle announced that the OnePlus 5 will be soon getting Android Oreo Beta.
Once Available (Open Beta Program for OnePlus 5), you'll need to do is flash the Oreo Beta firmware on your OnePlus 5. Once you migrate to the Beta path, you will continue to receive Open Beta OTAs. You will NO LONGER receive the regular Official Stable OTAs.
Carl Pei (Twitter)