Ey guys, your no-questions-asked favourite admin here. Everything's changing, so along with that, I'm here to ask you a question.
Have you updated to 1.7.6, 1.7.7, or 1.7.8?
Well, if you didn't, you probably shouldn't for now if you want to be able to access our server.
If you did, don't panic! You can easily go back to 1.7.4 or somewhere around there any time you want by clicking "profile editor" and setting up a new profile with the version you want to use. Personally I'm using Optifine with 1.7.4 and it's working great, but anywhere from 1.7 to 1.7.5 should probably work.
We're getting down to business on this fix as soon as possible (mostly it involves waiting until LibsDisguises supports the new protocol) - if you're using the versions I'm telling you to use and you can't get on the server, that probably means we've already fixed it.