Well I dont think it ever happen may b just for 1 day, Bcus now everything works same. Does anyone know when there will be new page rank update?
I don't think so. PR is the very important part of seo and google too. If your PR is high then chances of getting the traffic will be high.
Although PR is relied-upon heavily as a KPI, I agree it can be manipulated quite easily. I'd be surprised if Google did away with it overnight, but certainly the trend is towards producing high quality content on your site.
page rank is not much important nowadays because many people are using false techniques to change their page rank