Three months ago OnePlus promised that they would have updates for the OPO. It looks like OPO owners will have to wait just a little bit longer than the three months promised before they will see an update for their device. The CM12s build that brings the device up to Lollipop and also the OxygenOS builds should be available some time in March. The reason for the delay is states by co-founder "Carl Pei" to be proprietary drivers, code, quality assurance, and certifications that are needing to be altered from the alpha version. While you wait you could run one of many custom roms that are available for the device, or you could indeed run the alpha version that was released a while back. The stable version should be here soon. Just not as soon as promised.
via @getpeid