in their defense though, that was (and is - until the final RFC is released) true. Depending on your infrastructure (reverse proxies, firewalls) supporting just one version can already be painful.

Supporting different versions, incompatible to each other is even more painful.

And as a generic host you can't make all your customers constantly update their application especially when you consider that various browsers out there support (or don't support) different revisions of the protocol.