As you know, Google announced the launch of Penguin 4.0, the real time Penguin algorithm, on Friday September 23, 2016. Many want to know if it is fully rolled out - it doesn't seem so. Many want to know if it only started to roll out on Friday or if it started earlier.
John Mueller at Google wrote on Twitter that Google doesn't have a "start date" to announce for Penguin's launch. He said:
So I then asked did it roll out before September 23rd and Gary Illyes from Google asked, if it really matters:
If I had to guess, the rollout started a few days before the official launch but we saw signs of Google testing it even earlier. I honestly have no inside information, so that is just a guess.
Forum discussion at Twitter.