Google said in a post on Google+ that a “slow rollout” began earlier this week and will continue into next week, before being complete. Google said that depending on location, about 3%-to-5% of search queries will be affected.
Anything different about this latest release? Google says it’s supposed to be more precise and will allow more high-quality small and medium-sized sites to rank better. From the post:
Based on user (and webmaster!) feedback, we’ve been able to discover a few more signals to help Panda identify low-quality content more precisely. This results in a greater diversity of high-quality small- and medium-sized sites ranking higher, which is nice.
Source : Panda 4.1 - Google’s 27th Panda Update - Is Rolling Out