That has nothing to do with the protocol, crashing the server was obviously never part of the protocol.If the protocol was backwards compatible with <1.8.4, the server could easy be crashed with an NBT exploit. Send it too many nested NBT tags? Enjoy your OutOfMemory exception.
IGN: ZachTheUnkown
this sounds like it will screw up in the first months of its release, but to heck with it, Im gonna ride it down till the wheels fall off.
I bought Minecraft October 2010.