Fatal error: Uncaught Error: Call to undefined function wp_theme_has_theme_json() in /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4.3.1-ja-jetpack-undernavicontrol/wp-includes/script-loader.php:1634 Stack trace: #0 /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4.3.1-ja-jetpack-undernavicontrol/wp-includes/class-wp-hook.php(308): wp_default_styles(Object(WP_Styles)) #1 /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4.3.1-ja-jetpack-undernavicontrol/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters('', Array) #2 /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4.3.1-ja-jetpack-undernavicontrol/wp-includes/plugin.php(565): WP_Hook->do_action(Array) #3 /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4.3.1-ja-jetpack-undernavicontrol/wp-includes/class-wp-styles.php(135): do_action_ref_array('wp_default_styl...', Array) #4 /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4. in /export/sd07/www/jp/r/e/gmoserver/5/6/sd0044056/upthemark.com/wordpress-4.3.1-ja-jetpack-undernavicontrol/wp-includes/script-loader.php on line 1634