Google sends out pretty constant updates to their app and media store, and the latest went out just this morning, bringing the Google Play Store up to version 3.15.19. There's no changelog and no noticeable change from previous versions, so we wouldn't be in a hurry to force update your phone or tablet. Everyone in the US at the very least should be getting the update over the next couple of days, but if you must, you can download and install it here.
The biggest thing to hit the Google Play Store lately has been carrier billing for every major US carrier except Verizon, which was recently extended to books, movies and music. That happened more or less automatically, and the new update doesn't seem to affect it one way or the other. Unfortunately there's still no way to get carrier billing on Verizon, no matter how much modding you do - likely they're still holding on to their proprietary V-CAST service.
Updates to the Google Play Store (formerly the Android Market) are among the more mild mods one can do to his or her Android device - you don't even need root. Just check the Applications section of your Settings menu and make sure you've got outside sources available. We'll be updating this post if we find anything significant.
[via Android Police]