Is showcase category post per project? Or post per update? There is no information about that in the pinned post, so I thought it would be good addition there.
I don’t have a clear preference, that’s why I asked; I think both can work out. Per project is good from continuity perspective and not spamming, but on the other hand, each sizeable update being its own post brings more interaction for the latest changes.
I’d make it a post per update to your project, so that the replies to it can be comments on what’s new about it.
Otherwise it’ll become hard to find updates on the project if it’s lost within a sea of replies, and to avoid that you’d have to edit the original post, which isn’t going to make it immediately obvious there was an update.