Nobody knowns exact date. It can be from month up to half year. Last update was at the last month. So the next can be at the end of current year or at the beginning of the new one.
Never.... they have discontinued it To many "camel jockeys" trying to pimp page rank, so they will no longer offer it glad i could help laterz malcolm
Agreed with malcolm1, just continue building up backlinks, you will know when its updated.. Although there was one recent update, the next one can be around in 3 months or less.. Who knows.