In software terms, it sounds like you're working on something that's out of beta and essentially complete—but still pending any last-minute changes prior to publication.
This is often described as a release candidate.
From PC Magazine's definition of release candidate:
A pre-release version of software. Sometimes software vendors make one or two release candidates (RC1, RC2, etc.) available to select customers in advance of the official release. A release candidate is like a "sneak preview" of the final release with the added advantage that serious bugs may yet surface and be fixed before the general public uses it. Thus, there are alpha versions (internal), beta versions (external), release candidates (sometimes) and the final release of software. After that, there are countless updates that add features and fix bugs.
In editing terminology, a manuscript that has had its final round of technical input and copyediting is, as you've called it, a final draft:
: a final version of something (such as a document) usually after a lot of editing and rewriting
// The final draft is due tomorrow.
However, what you're currently working on is something prior to that stage—and certainly prior to the even more complete stage of proof or galley proof (which, in the publishing world, is what a final drafte turns into when it's sent to a typesetter).
In general editing terms, a draft that comes before a final draft is simply a manuscript.
I know of no editing terminology that is the exact equivalent of release candidate, but that is the analogous term that you're looking for.
Note that you asked for the initial version in your question—but also said that you want something that's the expected or target version. Those two things seem incompatible to me. But if it's not actually release candidate that describes your current situation, then you could make use of either alpha or beta, depending on how you are interpreting things. Or even initial draft. But, again, you seem to be describing things at two different ends of the development cycle at the same time, so I'm not certain. A target version is also known as a prototype or proposal.