It's sort off official? Google is not going to update the pagerank any more. This is as mentioned in 'English Google Webmaster hangout' by John Mueller. You can see the video here. For relevant part on pagerank see the video from 19 minutes onward.
The last pagerank Google did was in December 2013. As per Google that update also happened by accident and was not intentional. Pagerank has been the most obsessed term in SEO world and a whole industry works around it both in a legitimate and not so legitimate way. Google has been noticing the spam industry building around Pagerank with spammy backlinks.
Google still might be using the Pagerank internally but it's not going to expose it to the outside world now. Even Mat Cutts has hinted earlier that Google may not be updating the public PR ranks and it's increasingly becoming an official position
The most famous concept of search optimization industry may now just remain in the by-lanes of Google search algorithm. A whole generation will feel nostalgic about it in future. How much you feel impacted with it?