Unsupported feature of the database platform you are using.

Code:
public function backup()

    {

        $model = new class extends \CodeIgniter\Model

        {

            protected $table      = 'tb_envelope';

            protected $primaryKey = 'id_envelope';

        };

        $db = \Closure::bind(function ($model) {

            return $model->db;

        }, null, $model)($model);



        $util = (new \CodeIgniter\Database\Database())->loadUtils($db);



        $date= date('YmdS-His');



        $config = [

            'format' => 'zip',

            'filename' => 'My_' . $date . '_db.sql',

            'add_drop' => TRUE,

            'add_insert' => TRUE,

            'newline' => "\n",

            'foreign_key_checks' => FALSE,

        ];



        $backup = $util->backup($config);

        $file_name= 'My_' . $tanggal . '.zip';

        helper('download');

        $this->response->download($file_name, $backup);