=')) {
            add_action('admin_notices', array(__CLASS__, 'notice_min_wp_version'));
            return false;
        } else {
            return true;
        }
    } // check_wp_version
    /**
     * Check if user has the minimal PHP version required by WP Captcha
     *
     * @since 5.0
     *
     * @return bool
     *
     */
    static function check_php_version($min_version)
    {
        if (!version_compare(phpversion(), $min_version,  '>=')) {
            add_action('admin_notices', array(__CLASS__, 'notice_min_php_version'));
            return false;
        } else {
            return true;
        }
    } // check_wp_version
    /**
     * Display error message if WP version is too low
     *
     * @since 5.0
     *
     * @return null
     *
     */
    static function notice_min_wp_version()
    {
        WPCaptcha_Utility::wp_kses_wf('
' . sprintf(__('WP Captcha plugin requires WordPress version 4.6 or higher to function properly. You are using WordPress version %s. Please update it.', 'advanced-google-recaptcha'), get_bloginfo('version'), admin_url('update-core.php')) . '
' . sprintf(__('WP Captcha plugin requires PHP version 5.6.20 or higher to function properly. You are using PHP version %s. Please update it.', 'advanced-google-recaptcha'), phpversion(), 'https://wordpress.org/support/update-php/') . '