426 Upgrade Required
HTTP 426 Upgrade Required 客戶端錯誤響應狀態碼錶示伺服器拒絕使用當前協議執行請求，但在客戶端升級到不同協議後可能願意這樣做。
伺服器隨此響應傳送一個 Upgrade 頭，以指示所需的協議。
狀態
http
426 Upgrade Required
示例
需要從 HTTP/1.1 升級
給定對系統的 GET 請求
http
GET /resources HTTP/1.1
Host: example.com
源伺服器期望請求必須以 HTTP/3 形式發出
http
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.
規範
| 規範 |
|---|
| HTTP 語義 # status.426 |