Although the next PR update is way overdue, it's anybody's guess! But with my vast seo training (NONE) and my tremendous success at guessing the next PR Update (TOTAL FAILURE), I predict it will be September 16th. Hopefully, that answers your question and all past and future questions about PR update.
I was inspired by your thread to share my secret sanjog, so here is the amazing tool I use to predict PR Thread
Its over 4 months since google last shown PR, yet there are no signs of any PR. I am confidence in doing future projects.
Hey guys stop running after PR. We need to run after SERP See what Mr Matt Cuts speaks here: http://forums.digitalpoint.com/showpost.php?p=4391628&postcount=58
Have you contacted Google? Why ask in a forum unless Google employees are members here too? Otherwise you just get BS. lol But when you do find out from Google please let us know.
I like google to stop using PR. I don't see that PR is important in ranking anymore. PR is just useful for link sellers.