Google has said time and time again that you should not pay attention to the Google Toolbar PageRank score, but yet they have yet to zero-out any of the data, instead, they keep it as it was since the last accidental update back on December 6, 2013.
The last Google Toolbar PageRank update was over 14 months ago and before that, the last intentional update was on February 4, 2013, just over two-years ago.
Google has told us they won't be updating the metric and they probably won't update it in the future.
John Mueller from Google was asked this again at the 53:16 mark in a video hangout from about two weeks ago. The question was "When will be the next google PageRank update?"
John said, "Probably Never."
He said:
Probably NeverThis is something I think we're stopped updating, at least the toolbar PageRank that is shown. I don't know the future of the Toolbar in general, but at least from the PageRank side, this is probably something we're not going to update.
John then goes on to explain the accidental PageRank update. Then the webmasters ask him what is a good metric to look at instead and he doesn't give a clear answer.
Here is the video, so you can see the confident he had this time when answering:
Forum discussion at Google+.