Defective firmware causing unpressed keys to register on certain keys (my old comments on this are probably still in the Massdrop discussions for this.) They contacted me to try get a working update via email, but none of it worked. Then they stopped contacting me. This keyboard is unusable and has just been sitting in my storage since. Decided now (2018) to leave a review from my order in 2015 because at the time I thought they'd eventually get back to me--they never did and I eventually forgot about it.