If you don't have it yet, you really should get it. If you do have it, rush on over to the App Store and download the latest update if your phone hasn't automatically grabbed it yet. It's got two major quality of life improvements for serial Threes! players. First off, you can skip signing your name at the end of every game, to get right back in to your Threes! combining action. Additionally, a "+" now appears next to the upcoming card if it's going to be more than three.
The "+" is going to be awesome, as previously when a white card was up next you hoped it was a three, but it could be a bunch of different numbers that can really mess up your board state. The new "+" display will hopefully make late game Threes! a little less frustrating as now players will know for sure if they're getting a one, a two, a three, or something more than that.