I think it's fine to announce releasing a genuine update to the game. (Some people spam the same announcement repeatedly, and we frown on that, but it's not so common.) Just follow the rules, they're show in big bold text at the top of the page when you browse the category, and again when you post. Mostly, put some effort into it. Show you care. I often overlook the media rule when the project simply doesn't have a screenshot, perhaps because it's a boring-looking PDF.
What makes a good announcement that gets people to click through is another story. I had very little luck with my own.