I'm calling the latest release of Debstack version 2.0 as it is a fairly big rewrite compared to the original version. (Debtstack binaries; Introductory blog post on Debtstack; Current Debtstack code site) The big deal with this rewrite is it now uses a mostly immutable data model, plus a couple of basic new features.

Immutable Model

I realized that from the beginning I should have built Debtstack on top of a strongly immutable model, and its part of why I chose F# as the language to begin with. (I of course didn't quite follow through on that initially.) It really seems like the right way to go for this project, not least because provides better insight into how the algorithms work and easier debugging and asynchronicity, but more importantly because when dealing with financial data (even just for a read only viewer like Debtstack) it makes sense to try as much as possible never, ever, lose information or even to change things without a log of the change. It hit me early on in this particular rewrite process that essentially the immutable model that I'm using is an interesting (and logical) extreme form of double-entry accounting. I'm pleased at the idea that the code now largely resembles a long-standing accounting best practice.

New Features

Most of the new features exist largely because the new data model facilitates them.

Transaction details
Transactions now have an inspection window showing the complete breakdown of how the chosen algorithm affected them, by double-clicking them in the "Open" list up top or clicking the "Details" button in the grid of Closed items.
"Naive" algorithm
I refer to this as the "But You Don't Have to Take My Word For It" button. This presents the view everyone tends to calculate in their head when looking at a recent statement. This is the simple first in, first out queue view that the other two algorithms are designed to be more interesting in comparison to. I didn't see a use for it in the old version, but with the new immutable model it is a bit more interesting and a bit more useful to directly compare the results.
Date filtering
After choosing one of the algorithms to look at, you can now filter it back in time to see historical views ("What did my balance look like last month?", for instance).

Evolutionary Tangents

This version swaps ImpromptuInterface.MVVM for ReactiveUI and (my) ReflexUX, but neither is all that strongly used (because they don't really need to be, largely in part due to the new immutable data model) and for the moment the difference between the two dynamic MVVM backends is a wash for this project.

Full Disclosure

Since writing version 1.0 of Debtstack, I'm now employed by a credit card processing company. Debtstack is a hobby project for my own personal use and amusement. So far as I know the company I work for has no interest in Debtstack and certainly does not endorse it (and probably knows nothing about it). This project and any opinions espoused about it are entirely my own.

I don't think it matters to actually disclose it, and Debtstack has zero to do with the area of the company that I work in (Sales software), but it seemed somewhat relevant, and also I feel special now because I've never really felt I needed a full disclosure for some bit of Open Source work before.