HTTP Upgrade Header - HTTP/2

   The HTTP Upgrade mechanism is used to establish HTTP/2 starting from plain HTTP. The client starts an HTTP/1.1 connection and sends an Upgrade: h2c header. If the server supports HTTP/2, it replies with HTTP 101 Switching Protocol status code. The HTTP Upgrade mechanism is used only for cleartext HTTP2 (h2c). In the case of HTTP2 over TLS (h2), the ALPN TLS protocol extension is used instead.

PHP 5.4.16

   PHP: Hypertext Preprocessor is a general-purpose programming language originally designed for web development.

Character Encoding :UTF-8

   This website is using UTF-8 character encoding in HTML , character encoding is used to represent a repertoire of characters by some kind of encoding system.