Google has released the lastest of their updates, Penguin 2.1 which was launched on Friday 4th October 2013.

Matt Cutts announced this on Twitter stating that it will effect roughly 1% of searches.

This is the biggest update since Penguin 2.0 in May 2013 and has sent everyone in the SEO world into a panic. We are looking into what seems to be the 4th official Penguin update. Our research shows Penguin to have been rolled out 24th April 2012, 5th October 2012, 22nd May 2013 and now this update.

This update comes just weeks after Google released Hummingbird and this update is probably to help with the algorithm change.