After announcing its plans to release stable Android 10 sometime in the second quarter of this year for OnePlus 5/5T, OnePlus has now started rolling out the first Android 10 open beta for these devices. It is worth noting that these devices were launched back in 2017 with Android Nougat out of the box.
Brand new UI design brings light and fluid experience
Updated to Android 10
Newly added Hidden Bar to allow left-right switches of recent apps
You may download the open beta build for OnePlus 5 from here and OnePlus 5T from here. As is the case with all open beta updates released by OnePlus, you may download the update package and perform a local upgrade.
Meanwhile, the stable version of Android 10 must be right around the corner and hence, you may consider waiting for that instead to seamlessly upgrade your OnePlus 5/5T via OTA update.