426 Upgrade Required
HTTP 426 Upgrade Required 用戶端錯誤回應碼表示伺服器拒絕使用當前協定執行請求，但在用戶端升級到不同協定後可能願意這樣做。
伺服器使用此回應發送一個 Upgrade 標頭來表示所需的協定。
狀態
http
426 Upgrade Required
範例
http
HTTP/1.1 426 Upgrade Required
Upgrade: HTTP/2.0
Connection: Upgrade
Content-Length: 53
Content-Type: text/plain
This service requires use of the HTTP/2.0 protocol
規範
| Specification |
|---|
| HTTP Semantics # status.426 |