serRoyGbiv

Hello, first off im sorry if ive put this into the wrong place and if there already is one up i havnt been able to find a similar post that answers my question clearly. So first time ive installed tekkit and go i go to connect to any server and when i try to join it crosses out the green bar things and next to it says 1.3, and i would like to know if there is a way to fix it so i can join? thank you for reading it all and any answers are appreciated :D