OnePlus is good enough to provide a beta channel for its phones, so you can stay on the bleeding edge. You'll also probably encounter more bugs, but such is life. There are new Oreo-based Open Betas live today for OnePlus' recent phones. They include some functional updates as well as security patches.

All devices appear to share the same changelog, and here it is.

What's new:
System
  • Updated Android security patch to May
Launcher
  • Added Toolbox Card in shelf
  • Added Hidded Space in app drawer
  • Added support for editing dynamic icons(weather,clock and calendar)
OnePlus Switch
  • Optimized user interface for backup & restore
  • Optimized logic for time remaining
  • General bug fixes and stability improvements
Messages
  • Added Group MMS