I see deep implications here. If an origin advertises HTTP/3 support, it is saying "this origin is compatible with HTTP/3-only clients". HTTP/3 clients are not required to implement HTTP/2 or HTTP/1.1. WebSockets is a special case because it's old, and we can carve out some limited fallback due its legacy status, but in general I think we need to stick to this rule. Otherwise, the HTTP versions cease to be independent. Instead, we're effectively requiring clients to support _all_ HTTP versions. Also, I have doubts about the claims of server simplification. In order to tell the client "sorry, you need to use HTTP/X instead", the different server versions have to be pretty tightly coupled, to know which protocols are supported on which versions. At that point, you might as well just proxy the request to the version that knows how to handle it.
Received on Friday, 22 October 2021 02:08:24 UTC