CentralNotice esi <esi:include src="/esitest-fa8a495983347898/content" /> HTTP/1.1 Upgrade header From Wikipedia, the free encyclopedia Jump to navigation Jump to search HTTP header field introduced in HTTP/1.1 HTTP Persistence Compression HTTPS QUIC Request methods OPTIONS GET HEAD POST PUT DELETE TRACE CONNECT PATCH Header fields Cookie ETag Location HTTP referer DNT X-Forwarded-For Response status codes 301 Moved Permanently 302 Found 303 See Other 403 Forbidden 404 Not Found 451 Unavailable for Legal Reasons Security access control methods Basic access authentication Digest access authentication Security vulnerabilities HTTP header injection HTTP request smuggling HTTP response splitting HTTP parameter pollution v t e The Upgrade header field is an HTTP header field introduced in HTTP/1.1 . In the exchange, the client begins by making a cleartext r...