I haven't checked my site for 2 weeks. Then I noticed that it went from 3 to 4. That's great. This is one of those things, I had been checking every single day for the last 3 months. Then I got too busy to check for 2 weeks, now it's updated. I don't when it was updated though. It could be yesterday.
This thing happened to me ) I was checking the PR from hour to hour and I got busy for 2-3 days and the PR increased for my site... )
That's great especially if you did no backlink works during that period.. so they're all real organic back links!
it's a good news for you . if you start to build backlinks for , you can more money&pr for the next update