This is from Pete at AO
We've completed the first stage, which is the most difficult, making sure we can build a light module that the car is happy with. Now we need to make it brighter, and the first double-bright sample (#4) arrived yesterday. We have it on a test rig here for a week for soak-testing, then it'll going into a Model S for real world testing. If it's good, we can start to move forward with production, but honestly, it's rare that we get to a production sample in just 4 attempts, so I suspect we'll still have a couple more iterations to go through. My best, and vaguest guess would be "Spring" for launch.