OxygenOS 3.1.0 is now rolling out to the OnePlus 2 - but many owners of the handset have flooded its forums with complaints that various outstanding issues and bugs still haven't been addressed.
Oxygenos 3.1.0 RSS
Almost eleven months after Marshmallow was originally released, a preview build of OxygenOS 3.1.0 - based on Android 6.0.1 - is now available for the OnePlus X, but there are some known issues.