Define a PR update!

You see it happening, many people complaining that their sites have dropped PR, wouldn't that be considered a update? I would say so, if sites are seeing changes, it would be a update, whether your PR is rising or dropping, it is updating. Can anybody show me where Google states that all PR updates will be positive?

 

I think , that there is no way to tell for sure, I had PR change on 2 of my sites in July/August just like few other guys here, was that an update?
And that is where my #100 post is born made me berserker

 

I think it just some kind of testing update to test some new algo. surely they will have a big update later with many new changes and mostly will be a bad news due to paid links issues.

 

Pr will be updated for every 3 months. Then our rank will increase or drop

 

Forget pr update mate ,google doingsome updates
its damm boring ,same old thread

 

I think it was updating and some thing goes wrong and they are working on it to fix it up and hopefully they will update it soon.