I updated the TS3 Server today. Apparently the client needs to be updated too in order to work properly.
You can update your client either by using the internal application updater. (Help(MainMenu) -> Check for Update(MenuPoint)) You might have to run it a couple of times until it says you have the latest version.
Or go to their website and grab the client from there. Be aware it was quite crowded over there so download and page load might take some time.
If you still have any issues getting your client updated just reply.
Happy updating
