On December 6th 2013 Google has pushed out a Google PageRank update when no one was expecting it. The last official update was February 4th 2013 and the next one was due August 2013. After this didn’t take place it seemed that Google had changed its focus and this has taken all webmasters by suprise.
Matt Cutts has actually confirmed on Twitter that this update was a kind of accident by Google:-
Webmaster should now be checking the whether the Google Page Rank has dropped.