I have Aperture 2 box. Can I upgrade to 3.4.5 free?

Just curious if this is possible, or if I'd need to have a previous version of Aperture 3 to update to 3.4.5. I've been waiting to pull the trigger on Aperture 3 for quite some time. So if it's free now, why not? I don't see it in my Software Update. I've heard Apple was having issues updating people with the box editions.