39 hours later.Still no download, still no reaction from GOG. It's sad: GOG offers something, and then doesn't deliver, nor bothers to inform customers about why not. Aside from legal questions, these are not respectable business ethics.
Guys, I have spent money to be able to play the old version first, and then the new one (if I like the old one), and I will not download the new version before the old one. If it takes too long to give me the old version, I will request a refund.
I'm running out of patience - there may be good (or bad) reasons why you can't offer the old version for download right now, but there is NO reason why you can't or shouldn't inform your customers.
How would you react, if you bought something in a store, and what you get is missing one of the features announced, which happens to be the one feature that made you buy the product? I don't think you're cheating deliberately, but you're very close to losing at least one customer.
Until now GOG is my favourite platform for obtaining games (and I have quite a few) - this may change if you don't resolve this issue.