There are multiple versions. I suggest you get these from the official site (free, but donations support the cost of equipment, purchasing film reels, and HDD space) and make sure you have the most recent 4K version. I don’t think you will know with certainty which version you have if you try to get this through other means.
I get the sense it was a tricky restoration due to the film stock (and film scanning equipment) they had available, which was spread across 16mm, Kodak 35mm, and Fuji 35mm (which had better colour preservation but was incomplete). They explain it much better on their website, but it is an iterative process, and earlier versions might have a different quality.
Darn. I have no idea where I got my code and don’t have one to share (I just looked on my profile). It looks like others have helped out. FYI the latest 4K version (1.0) is from February…