I doubt they'll be having a "beta" for a patch that so radically changes the netcode for SINS. It's not something that can only half-work! It needs to be "fully-cooked" the moment it is released to the public.the Monk
Well according to several posts from Yarlen, there will indeed be a public beta test of 1.1 just for the net code.

I would definitely assume it's optional, however.