It is officially well over 18 months, a year and a half since the last official Google Penguin update. The last Google Penguin update was on October 17. 2014 - Penguin 3.0. Since then, any site hit by that, probably has been in serious trouble financially and probably had to take major losses over the past 18 months.
We know the folks at Google are done estimating when Penguin 4.0 will launch, since Penguin 4.0 was expected to launch this past quarter but before that we expected it in January and then in 2015. None of that happened and now 18+ months later, we are still waiting.
Google seems so fed up about these algorithm updates that they don't want to announce future ones. In fact, Google said the next Penguin update, will be the last.
Yesterday, Gary Illyes responded on Twitter about it again:
@johnstez ya, I am. But no, we can't
— Gary Illyes (@methode) May 9, 2016
For more about this topic, see our Google Penguin category.
Forum discussion at Twitter.
