wp_get_server_protocol() │ WP 4.4.0

Returns the HTTP protocol sent by the server.

No Hooks.

Return

String. The HTTP protocol.0.

Usage

wp_get_server_protocol();

Changelog

Since 4.4.0 Introduced.

wp_get_server_protocol() code WP 6.5.2

wp-includes/load.php 
function wp_get_server_protocol() {
	$protocol = isset( $_SERVER['SERVER_PROTOCOL'] ) ? $_SERVER['SERVER_PROTOCOL'] : '';

	if ( ! in_array( $protocol, array( 'HTTP/1.1', 'HTTP/2', 'HTTP/2.0', 'HTTP/3' ), true ) ) {
		$protocol = 'HTTP/1.0';
	}

	return $protocol;
}