The Upgrade header field provides a mechanism to transition from HTTP/1.1 to another protocol on the same connection. For example, it is the mechanism used by WebSocket's initial HTTP handshake to establish a WebSocket connection.
The Upgrade header field provides a mechanism to transition from HTTP/1.1 to another protocol on the same connection. For example, it is the mechanism used by WebSocket's initial HTTP handshake to establish a WebSocket connection.