It seems like the folks at Cyanogen have been working much harder than the ones behind OxygenOS, since the 2015 dispute between OnePlus, Cyanogen and Micromax did not slow Cyanogen down from pushing out Marshmallow to the OnePlus One, earlier than the still pending OxygenOS for the device.
The first flagship killer by the Chinese startup will finally be receiving Cyanogen OS 13, powered by Android Marshmallow. According to OnePlus, the update would be rolling out by now so those who are still rocking the One should start checking for OTA updates. The OTA update will only be available to those who are running on CM 12.1, meaning users who have made the switch to OxygenOS earlier will have to wait for their version of Marshmallow to arrive, unless you’re willing to wipe out your OPO, and flash CM 13 manually.
The Android Marshmallow update will include additional features native with Marshmallow, including Google Now on Tap and Doze which will save you some battery juice. Do note that if you’re already running CM 13 nightlies, Cyanogen advises against applying the official CM 13 release update since it might mess with your device, causing it to crash. The full details regarding the update is available here. Till then, stay tuned!
Source: OnePlus