Why did I get this error when I send an email with PEAR Net_SMTP module?

I get this error when sending emails with the PEAR Net_SMTP module:

Fatal error: Call to undefined method Ne开发者_运维问答t_SMTP::getGreeting() in /home/test/Mail/smtp.php on line 316

You might have an out dated version of Net_SMTP

In V1.4.4 we have that method like so:

/*
   * @since   1.3.3
*/
function getGreeting()
{
    return $this->_greeting;
}

But as you can see it was only add in V1.3.3 so you must have that version or greater.

@Source