PHP Parse error: syntax error, Unexpected '[' - PHP 5.3.29

Question

I have an application running perfectly locally. But when I played it online I keep getting the following message and I have no data return.

PHP Parse error: syntax error, Unexpected '[' in /var/www/reporters.intercol.com.br/_app/Models/Reportarioos.class.php on line 118

My PHP version is 5.3.29

and the code in question would be.

private function _getTipoOs(int $codostipo){
       $tipoOS = new Read();
       $tipoOS->ExeRead($this->empresa, 'mk_os_tipo', 'WHERE codostipo = :cot', "cot={$codostipo}", "descricao");
       $this->result = $tipoOS->getResult()[0];
       return $this->result["descricao"];
    }

I thank everyone who can help.