Google Penguin is a code name for Google algorithm update. The main aim of Google Penguin is to decrease the search ranking of websites which violates the Google Webmaster Guidelines. On 23rd September 2016, Google confirmed Penguin 4.0 is rolling out together in all languages at real time. Penguin is now real-time and granular.
Here's a simple timeline with Penguin Version Release Dates.
Penguin 1.0 : 24th April, 2012
Penguin 1.1: 26th May, 2012
Penguin 1.2: 5th October, 2012
Penguin 2.0: 22nd May 2013
Penguin 2.1: 4th October, 2013
Penguin 3.0: 17th October, 2014
Penguin 4.0: 23rd September 2016