OnePlus have announced that the latest version of Cyanogen OS, Cyanogen OS 12.1 (based on Android 5.1), which is currently undergoing testing and Google certification.
On the other side of things OxygenOS, which is OnePlus’s own operating system update based on Android 5.1, is in the works. Sadly you’re going to have to wait a bit as it won’t hit the OnePlus One until sometime after the elusive OnePlus Two arrives.
The entire team is currently heads down working on the release for the upcoming OnePlus 2. We are very excited about the work we’ve done and can’t wait to show you all the new features and improvements we’ve made. We have a small team which means in order to do our best work, we need to focus. This unfortunately means that we won’t have an OTA for the community build of OxygenOS we released back in April for the OnePlus One until after the OnePlus 2 release.
Finally, OnePlus say that a fix is coming for OnePlus One users who are experiencing touchscreen issues with their device. There’s no timeline on when it will arrive (other than “soon”), but both OxygenOS and Cyanogen OS will receive the minor update. It’s a bit of a mess, but at least OnePlus is being quite transparent about where it is with the updates.
Source One Plus Forums