426 Upgrade Required
The server refuses to perform the request using the current protocol but might be willing to do so after the client upgrades to a different protocol.
The server MUST send an Upgrade header field in a 426 response to indicate the required protocol(s)1
Example:
HTTP/1.1 426 Upgrade Required
Upgrade: HTTP/3.0
Connection: Upgrade
Content-Length: 53
Content-Type: text/plain
This service requires use of the HTTP/3.0 protocol.
- 1 Upgrade RFC7230 Section 6.7
- Source: RFC7231 Section 6.5.15
426 Code References
-
.NET HTTP Status Enum
HttpStatusCode.UpgradeRequired -
Rust HTTP Status Constant
http::StatusCode::UPGRADE_REQUIRED -
Rails HTTP Status Symbol
:upgrade_required -
Go HTTP Status Constant
http.StatusUpgradeRequired -
Symfony HTTP Status Constant
Response::HTTP_UPGRADE_REQUIRED
