The last Google Toolbar PageRank update was 11 months and 18 days ago, almost a year ago, on December 6, 2013. Google's John Mueller has told in a video hangout that there probably won't be PageRank updates in the future.
But now, John Mueller wrote it out in a Google Webmaster Help thread saying Google "have no plans to do further updates," around PageRank. He even said webmasters and SEOs should stop using "PageRank or links as a metric" around their web sites.
Here is the full quote:
I wouldn't use PageRank or links as a metric. We've last updated PageRank more than a year ago (as far as I recall) and have no plans to do further updates. Think about what you want users to do on your site, and consider an appropriate metric for that. http://googlewebmastercentral.blogspot.ch/2011/06/beyond-pagerank-graduating-to.html
Forum discussion at Google Webmaster Help.