/* http protocol version */
php_http_option_register(registry, ZEND_STRL("protocol"), CURLOPT_HTTP_VERSION, IS_LONG);
+#if PHP_HTTP_CURL_VERSION(7,64,0)
+ php_http_option_register(registry, ZEND_STRL("http09_allowed"), CURLOPT_HTTP09_ALLOWED, _IS_BOOL);
+#endif
/* timeouts */
if ((opt = php_http_option_register(registry, ZEND_STRL("timeout"), CURLOPT_TIMEOUT_MS, IS_DOUBLE))) {