Papi_Loader::deactivate PHP Method

    public static function deactivate()
    {
        // Remove Papi from plugins_loaded action.
        remove_action('plugins_loaded', 'papi');
        // Load deactivate_plugins if it don't exists.
        if (!function_exists('deactivate_plugins')) {
            include_once ABSPATH . 'wp-admin/includes/plugin.php';
        }
        deactivate_plugins(PAPI_PLUGIN_BASENAME);
        wp_die(esc_html__('WordPress 4.0 and higher required to run Papi! The plugin has now disabled itself.', 'papi'));
        // Remove instance.
        self::$instance = null;
    }

/**
 * Return the instance of Papi to everyone.
 *
 * @return Papi_Loader
 */
function papi()
{
    if (version_compare(get_bloginfo('version'), '4.0', '<')) {
        Papi_Loader::deactivate();
    }
    return Papi_Loader::instance();
}