Google released Penguin 4.0 almost after 2 years past their Penguin 3.0 update in October 2014. It is the last release in this type and major update of penguin as its a real time signal operated within its own core search engine algorithm.
Google introduced spcial filter in 2012 to track the spam sites which can not be tracked by its spamming system placed within its core search algorithm. This special filter was named as Penguin and it was operated on specific time intervals to detect and take actions on spam sites or spamming activities.
As penguin was not the realtime program, websites used to get penalized for minimum time period of 6 months to one year untill and unless next version of penguin is run. Because of which even if website stopped all spamming activity and removed all suspected links then as well they used to be suffered till the next release. For example last update from Google was Penguin 3.0 and it was released in october 2014 almost 2 years back that means sites who got affected by penguin 3.0 were still penalized till this release in 2016.
But now Google says, its new penguin 4.0 is realtime and operates in its core search algorithm so if websites have changed their content and removed bad links from their websites then they can be free from penalization very soon i.e. in realtime.
This new update is more specific in terms of its policy of penalizing site. It may not penalize whole website but it may affect some specific pages or even wider swath of website depending on the scenario. The filter is now more granular and can track spam signals and penalize the website accordingly or it may even just reduce ranking for few affected pages.
Google will not announce any further updates regarding penguin because now its a regular process as the filter is now a part of its core search.
This update from Google is not yet fully live but it may be live completely in next couple of weeks.
Reference – http://searchengineland.com/google-updates-penguin-says-now-real-time-part-core-algorithm-259302