通用滚轴wordpress主题免费版的错误讯息

站长你好，我的wordpress是4.8安装完主题后右侧上方会显示错误

Warning: Declaration of header_menu::start_el(&$output, $item, $depth, $args) should be compatible with Walker_Nav_Menu::start_el(&$output, $item, $depth = 0, $args = Array, $id = 0) in C:\xampp\htdocs\wordpress\wp-content\themes\Generalroller_free\widget.php on line 103

请问该如果解决呢?