Enable HTTP/2

serverutil/tls.go

@@ -123,6 +123,7 @@ func (c *TLSServerConfig) TLSConfig() (*tls.Config, error) {
 		CipherSuites:             serverCiphers,
 		MinVersion:               tls.VersionTLS12,
 		PreferServerCipherSuites: true,
+		NextProtos:               []string{"h2", "http/1.1"},
 	}
 
 	// Require client certificates if a CA is specified.