I have found that Qt doesn't support status code 308. I was wondering why that is. I'm also aware that not all subtasks of the "Implement HTTP 2" Qt task are completed. So, if 308 was introduced in HTTP 2, I will beware that doing a custom implementation of 308 in my Qt app might be near-impossible.
I have checked the HTTP 1.1 spec and it seems 308 is absent there.
Am I right in deducing 308 was introduced in HTTP 2?
1) RFC 2616 isn't "the" HTTP spec anymore. It has been obsoleted a few years ago by RFCs 7230 etc.
2) Status codes do not need to be defined in the base specs; 308 is defined in RFC 7538. The list of assigned status codes is at https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
3) And no, there's no direct relation to HTTP/2. In general, status codes are independent of the protocol version.