[fulafel]

There's new features in IPv6 but if you don't use them, it's pretty just more bits as far as applications and users can see. The biggest change is probably replacing ARP, but that part has been unchanged and shipping since the start and invisible to users. And of course there's also simplifications vs IPv4.

The biggest shock is for people who have gotten the NAT stockhold syndrome (which always went against IPv4 internet architecture, there's a reason it's outlawed in the standard track IP RFCs).