C4 competitive upgrade - Trade IN for Emagic Logic

I just remember that my Steinberg Cubase 4 is a trade-in back from the days when Emagic was sold to Apple.
I don’t remember quite how it went by, but I think you had to send in the front page of the Emagic Logic manual.

Is it okay for me to sell my Cubase 4 now, then?
Or does the license prohibit it?

It does say “Cubase 4 full version” on the receipt, so I suppose it’s alright to sell it.