Quentin Le Menez Messages: 22 Registered: September 2014 Location: Paris Saclay, France
Very strange as I do not recall releasing any such version. Where did you hear about a Papyrus 2.0.4 ?
As for the update site you can find it here  (its a composite so it might be the one that you have referenced in your eclipse). As for the website/documentation and the release dates you can find them here  and there  respectively.
There usually are three service releases after the first one but each individual project can do more after those if necessary.