The new Surface Pro 4 and Surface Book devices from Microsoft already have firmware updates ready to download from Microsoft. However, the older Surface Pro 3 has a new firmware update of its own that's currently rolling out via Windows Update.
At the moment, there's no word on what's new, improved or fixed in this firmware update for the 12-inch tablet. In addition, Microsoft is rolling out an update for the Surface Ethernet Adapter. We will update this post as soon as we get more information.
Thanks to "mkmaster78" for the tip!