It looks like the Android-running Nokia X has gotten its first update. The 16MB package is mostly dedicated to dealing with a particular shortcoming of Nokia's UI design. Did you notice that each row of app tiles comes in the same color, while all native apps' icons are white? While this gives it a uniform look, it makes the Nokia X's homescreen pretty disorientating, even after you get used to it.
Users complained, Nokia listened, and there you go - the new update lets you change those tiles' colors as you wish. Unfortunately, this applies only to third-party apps. Still, after installing, long-press on a tile, and tap on the small color wheel to the bottom right. You're set. The available shades are dark blue, pink, purple, orange, green, and sky blue.
If you haven't received the update, use the Settings -> About Phone -> System updates menu to check manually. We don't know whether the other X-series phones are getting the update, but we assume Nokia will take care of them as well.