I don't think they would say if any special offers are coming soon, but there are always discounts for upgrades. I just upgraded from DO11 to DO12 about a week ago, and it was ~$37 US, IIRC. I would've upgraded much sooner, but I had no income at all until recently.
I've always gotten just about every single upgrade (if not every single one) since DO's roots on the Commodore Amiga (~1990 or so). I have always considered DO to be just as essential as the operating system itself.. Maybe even more essential.
On that note, are there ever going to be any loyalty rewards/discounts??