Which address type is used in IPv4 but is not used in IPv6?

Multicast is supported in both IPv4 and IPv6; IPv6 actually expands multicast use to replace broadcast functionality.

IPv6 was designed without broadcast addresses to reduce unnecessary traffic and improve network efficiency. Functions previously handled by broadcast in IPv4 - such as address resolution and router discovery - are handled in IPv6 using targeted multicast groups (e.g., solicited-node multicast). IPv6 supports unicast, multicast, and anycast, but broadcast is not part of the IPv6 address architecture defined in RFC 4291.

Anycast is supported in both IPv4 and IPv6, though it is more formally defined and widely used in IPv6.

Unicast is a fundamental address type used in both IPv4 and IPv6 for one-to-one communication.