O so many similar threads about the Google update, i think only Google and God knows, you'd better search the forums and no need to post a new thread..
As they make ~500 algorithm changes a year, I will take a wild guess and say that there was one today and probably another one tomorrow.
Well, as others told here Google himself knows how many updates it would take up. But based on my study over some forum I think this penguin 2.2 itself will keep roll out for some time now. I suggest you become member of a good SE forums and keep track of the posts by experts, this would keep you updated on the SE world. Look below to some of the well known forums here below: http://searchenginewatch.com/ or http://www.seroundtable.com/ or you can search for search engine forums to get more list. But I do follow searchenginewatch and seoroundtable I get information about future updates and other good tips about search engines.
Try this: https://forums.digitalpoint.com/threads/when-will-google-next-page-rank-update-2013.2654714/