I think google update new page rank 4 times in a year. i checked some updates. But i am wondering now when Google going to give the next update can any one here tell me about this?
Last update made for pagerank was in september by Google so if the criteria is after every quarter, then it might roll out new update for PR in December.
I don't think they do it quarterly as you say. The ones we know of were in September, as well as November. It's like their algorithms, people gain PR all the time. It happens daily, not quarterly.