Update [September 28, 2016]: being such an old device now, OnePlus One had little mention in the OnePlus Reddit AMA that took place yesterday. Android 7.0 Nougat Nougat is definitely not coming to OnePlus One, as is the case of OnePlus X too, because of some, which means that none of the Snapdragon 800/801 powered devices will benefit the official Nougat update.
Original article [August 3, 2016]: The original OnePlus One device never got to go beyond the Android 5.1.1 Lollipop update which came with its OxygenOS 2.1.4 update, but today, everything changes, for good. Awesome developer pradeepsmehra was able to port the OxygenOS 3.1.0 update from OnePlus X, and with that, not only do OnePlus One users get to experience latest OnePlus UI and features, but they do with the Android 6.0.1 Marshmallow update (otherwise available as Cyanogen OS only).
To install the OxygenOS 3.1.0 build on your OnePlus One, you will need to have TWRP recovery installed. If you don’t have it, go ahead and grab that first. Once you have that, go to the official development page below, and download the ROM, and root files if you look forward to root your device on OxygenOS 3.1.0.
If you need any help with installation, sure ask in comments below.
OnePlus One Nougat update?
Well, that’s not gonna happen most probably. The OnePlus One a 2+ year old now, and that’s the stage when you can’t expect the manufacturer to roll out major Android OS updates for you.
Sure, there will be unofficial updates available, like CM14. And maybe a port of official OnePlus 3 Nougat update. But right now, we have to wait. Only wait — which is killing, we know! If you want a date to hang on to, watch out for the end of this month, which is when we think an almost-daily-driver type of AOSP ROM should be available for OnePlus One running Android 7.0 underneath.