この記事はまだボランティアによって 日本語 に翻訳されていません。ぜひ MDN に参加して翻訳を手伝ってください!
この記事を English (US) で読むこともできます。

The HTTP 426 Upgrade Required client error response code indicates that 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 sends an Upgrade header with this response to indicate the required protocol(s).

Status

426 Upgrade Required

Examples

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

Specifications

Specification Title
RFC 7231, section 6.5.15: 426 Upgrade Required Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content

See also

ドキュメントのタグと貢献者

このページの貢献者: teoli, fscholz
最終更新者: teoli,