What happend to some of the older courses?

Hi there,

I'am currently thinking about resubscribing to CG-Cookie, because I want to start again with blender and unity. Since the last time I was here, the site has changed much and I also noticed that some of the older courses and tutorials are gone. For example, I know that there was a course about modeling a sci-fi-vehicle (some kind of green "helicopter"). Is there a reason why it's gone? Maybe it was outdated?

I ask because I'm not sure if I can watch tutorials in the future again, or if they maybe got removed after a while.

Greetings