According to Search Engine Land who broke the news … “The fourth release of Google’s spam-fighting “Penguin Update” is now live. But Penguin 4 has a twist. It contains Penguin 2.0 technology under-the-hood, which Google says is a new generation of tech that should better stop spam.”
Penguin 4 on May 22, 2013.
Do you remember when first Penguin updates happened? http://on.fb.me/11fYNaI