How to update Chrome OS in Parallels Desktop 6

[HoraceC]

Hi
I just downloaded a version of Chrome OS that was in Parallells desktop.
It was like this:

After Downloading, I saw that this version was not the latest Chrome OS, and I tried to upgrade it.
After this, I don't know how to upgrade it!

I tried clicking on the wrench and clicking About Chromium, but there was nothing about an upgrade.

Here's another picture:

Is there anyway to upgrade the Chrome OS?

Thanks.