Google’s Gary Illyes confirmed by his tweet that Google is rolling out his panda refresh 4.2. Please check the tweet here
Google confirmed that the roll out began at Saturday and it will take months to roll out fully. This is site-wide update it affects to website site wide. In Panda update Google is check content quality of the website and take action against those are having low-quality content, Thin and duplicate content. So always try to build good quality fresh content.
This update is slowly rolled out and they did not open, why is this update slowly roll out. It affect 2-3 % query.
Last update was happened in Oct 2014. So after 10 months this update is happened.
This update up traffic for some website those are doing well in the content world. Or may down for some website results, which are not having good quality content.
For more Panda update check here