I am the author of PHPMailer up to version 5.1 released November 10 2009. That version remained in use until 2011.
The History page lists all of the public releases of PHPMailer, starting in 16 April 2001 and up (note: I stopped tracking releases in 2014).
A better solution is here now. It's all in one single file and less than 80 Kb. PHPMailer Pro gets things back on track. A secure email transport class. Version 1.1.0 is one single PHP class that contains everything needed. SMTP support is built in. The default is now SMTP. And its automated. If SMTP fails, Sendmail is used. PHPMailer Pro supports SMTP in two ways: unauthenticated (the default) and authenticated.
To maintain as much of your legacy code as possible, there is a PHPMailer compatibility extension for PHPMailer Pro that does just that.