We all already knew OnePlus would be switching from Cyanogen to its homebrew ROM for One after a dispute. The ROM that got branded as OxygenOS was supposed to arrive in the last month but it missed the deadline because of its extended testing. Looks like all essential is now done as OnePlus has made OxygenOS available for the public. But, switching from CyanogenMod to OxygenOS isn’t an easy task, to be honest. Thankfully, there is a detailed guide by OnePlus itself which you can follow to flash the ROM. You’d still need to know what you’re doing if you don’t want to brick your One.
OxygenOS is based on Android 5.0.2 and in the current form it’s mostly bare-bone Android with just few touches here and there. OnePlus has kept its lightweight and functional.
So, go ahead and use it and let us know how you find OxygenOS.