joining 14w18a server that has 14w17a world, crashes my client not the server.

I updated my minecraft server to 14w18a. I didnt feel like restarting the world so I left it. When I joined the server, 3 seconds later it would crash my Minecraft client, but the server was still running.

What I expected to happen was...:
I expected to login to my server and play minecraft.

What actually happened was...:
I logged into my server and my Minecraft client crashed.

Steps to Reproduce:
1. create a server with 14w17a.
2. Then update the server to 14w18a. (do not change the world)
3. Join the server with 14w18a.