Let's say, DirectX 4.0 is never released; Microsoft launches DirectX 5.0 instead. So DirectX 4.0 is like a very special version of DirectX that is never made public for whatever reason.
Is there a word for an act like this (preferably a verb), or for an unreleased version of that kind (preferably a past participle)?
More generally, you have made a product, version 1.0. But you decide that it should stay unreleased. You make a better version 1.5 and release that one. Is there an apt word that describes (what happened to) version 1.0?