We heard back at the beginning of December 2015 (see Update 3 in that post) that the Google Penguin Real-time update was not going to take place before the end of the year, despite initially indicating that would be the case. They now say that it will be delayed further until full testing of the new algorithm is complete.
Editor's note - 6th January 2015: It looks like we may have spoken too soon. There is now some chatter that Google Penguin is rolling out in the US today. See this post for more information. (Edit: No it hasn't).
Then on December 11th John Mueller indicated that he was confident that it would be rolled out in January, although he stressed he did not wish to make any promises:
Um, I don't want to make any date promises but I am hopeful that things are lined up. Since it was kind of on the edge for this year, I'm pretty confident that that's good enough for January. But I really don't want to make any announcements on that.
Fast forward to January, and in a rather humorous style, Elkees Media asked the question directed at Gary Illyes, "I can see your penguin is ill from last one year. Will it be ok this month? I mean will it come in an update?"
Gary Illyes responded to the Elkees Media in a similarly humorous fashion, saying that "the Penguins are getting closer to freedom, but we don't have a specific date yet."
In a follow-up to that tweet, Gary Illyes further clarified that they couldn't release something that has not been tested extensively.
This implies that it may be some time before the update is forthcoming. We suspect that the update will not roll out this month (as previously indicated).
It is not uncommon for Google to delay the launch of planned updates for " technical reasons ", but with the launch date (albeit, unconfirmed indications) being put back on multiple occasions we wonder if they are having difficulties making the "Real-time" aspect of the new update work.
We further contemplate that with all the negative SEO (mass link spamming against competitors) that has happened since the last Penguin Update, back in October 2014 whether Google is having difficulty distinguishing between legitimate websites hit by spam attacks, and the spammers themselves. This, of course, may be just a matter of fine tuning that is the cause of the delay, rather than anything significant.