As usual Mojang decided to do their update catastrophe and break minecraft entirely, once again.
1.7.7/1.7.6 at the moment have a bug in them causing them to error out saying "Outdated server, pretending to be 1.7.7" or similar errors, I've personally tested this and its a bug seen and reported across other major minecraft networks, an easy fix for this is downgrade to 1.7.5, which can be done easily using the default minecraft launcher.
Under the profile section of the launcher click "Edit Profile"...
1.7.7/1.7.6 at the moment have a bug in them causing them to error out saying "Outdated server, pretending to be 1.7.7" or similar errors, I've personally tested this and its a bug seen and reported across other major minecraft networks, an easy fix for this is downgrade to 1.7.5, which can be done easily using the default minecraft launcher.
Under the profile section of the launcher click "Edit Profile"...