I'm not sure how you would get every HTTP/Cookie library to correctly follow a new RFC. There is a lot of software out there that is old and not well maintained

I'm not sure how you would get every HTTP/Cookie library to correctly follow a new RFC. There is a lot of software out there that is old and not well maintained that will still be around in another decade. I haven't read the HTTP/2 RFC's but with any luck they are 8-bit clean, which would be progress.