Game crashes when trying to connect to servers with 1.7.10 update

I really don't know why this happened now when I was able to connect to a server using the 1.7.10 update. Everything was fine for that one day but when I tried to reconnect to it, it crashes and sends me the full report on what happened. I'm not sure how it will help me but, I was wondering if there was a way for me to connect back to servers that are still stuck in 1.7.10.