Stateless: it is meant for hosts that generates it's own address.
Stateful : it is meant for hosts that obtain address from outside (external servers).
In IPV4 , DHCP provides this facility of giving IPv4 address to host.------------Stateful
In IPV6, DHCPv6 provides IPv6 addresses to host.
and further in IPV6 without use of external servers IP address is obtained,via Link-local address and other mechanisms.
So IPv4 is stateful and IPv6 can be stateful and stateless.
