OnePlus released its own OS today: OxygenOS. This should've been released a few days ago, but due to verificationproblems the release was delayed. With OxygenOS, Oneplus brings lollipop (Android 5) to the one.
Cyanogenmod, the default OS of the one, still hasn't released Cyanogenmod 12.

Currently you can online manually flash OxygenOS. Members of the comunity are allready working on installers, so I can probably tell you more in the near future about this.

Oneplus wanted to go back to the basics with OxygenOS. Like they said themselves: "We place things like performance and battery life over gimmicks and bloated features." This emphasize this is a initial release and they want the feedback of the community to expand OxygenOS.

The blog with all the information: https://blog.oneplus.net/2015/04/oxygenos-is-here-2/

What do you guys think about this? I'm probably going to install it, so expect a blog soon!

That's certainly a pity. They do have a feedback app you can install. They emphasized that this is a initial release and are still adding features. Hopefully this is going to be fixed in the near future.