Minecraft has been updated with a minor release, bringing the version up to 1.3.1 up from 1.3. The release is made specifically for modders, and modders only. Regular players will not have to download the new version of the game as it does not contain any new features.
According to Mojang, the new version of Minecraft fixes something called “obfuscation” and some issues too minor to list. The developers also added the following warning:
“This release is for experienced users only! It may corrupt your world or mess up things badly otherwise. Only download and use this if you know what to do with the files that come with the download!”
If you’re a modder, be sure to pick up the Client here, and the Server here.
If you aren’t, just go back to doing whatever it is you’re doing and pretend this doesn’t exist.