http://i3xi5qxvbrngh3g6o7czwjfxwjzigook7zxzjmgwg5b7xnjcn5hzciad.onion/proposals/224-rend-spec-ng.html
Furthermore, operators can use proposal 255 to load balance their
hidden services on the introduction layer. See [SCALING-REFS] for further
discussions on this topic and alternative designs.
1.6. In more detail: Backward compatibility with older hidden service
protocols
This design is incompatible with the clients, server, and hsdir node
protocols from older versions of the hidden service protocol as
described in rend-spec.txt.