Yeah, it's from Seiki as I already said. If you don't trust the download link, simply goto Seiki's Facebook page, give them your model and serial number, and they'll give you a link.
As for testing, it's what new se39uy04 TVs come with. Unfortunately it doesn't solve the frame skip issue when running your desktop in 120Hz mode. I verified that you still need to use the 50" firmware for that. But, the overall desktop and text looks better with this new January firmware. The 50" firmware causes slowdowns with the remote, menu is slower to load, choosing options goes slower and desktop looks worse but you get full 120Hz support.