There seems to be one other new thing: "Any QUIC endpoint that supports QUIC version 2 MUST send, process, and validate the version_information transport parame

There seems to be one other new thing: "Any QUIC endpoint that supports QUIC version 2 MUST send, process, and validate the version_information transport parameter specified in [QUIC-VN] to prevent version downgrade attacks.", with that QUIC-VN being another draft which also seems to have been approved for publication at the same time (https://datatracker.ietf.org/doc/draft-ietf-quic-version-negotiation/ https://datatracker.ietf.org/doc/draft-ietf-quic-version-neg...). So if I understood it correctly, what's actually new is the version negotiation mechanism, with QUIC version 2 being its first user.