Codeigniter email message – characters replaced with equal signs

When using CodeIgniter Email class, I have some characters replaced by equal signs (=) .  To avoid this use below code:

$config = array (

‘mailtype’ => ‘html’,

‘charset’ => ‘utf-8’,

‘crlf’ => “rn”, //Notice double quote to enclose rn

‘priority’ => 3 );

$this->email->initialize($config);