The Social Engineering Toolkit (SET) is a python-driven suite of custom tools which solely focuses on attacking the human element of penetration testing. It’s main purpose is to augment and simulate social-engineering attacks and allow the tester to effectively test how a targeted attack may succeed. The Social-Engineer Toolkit v2.0 released on December 1, 2013. The latest version of the toolkit has been released on July 4, 2013, with the latest version being released on January 1, 2014.
Source: https://thehackernews.com/2011/08/social-engineer-toolkit-v20-released.html