initial commit

docs/adr/adr-tax-year-2024-development.md

@@ -0,0 +1,34 @@
+# Direct File Development 2024
+
+Date: 06/14/2024
+
+## Status
+
+## Context
+
+In our current state, Direct File cannot support filing taxes for two different tax years. That is, we cannot
+make changes that expand our tax scope or prepare us for TY 2024 without causing breaking changes to TY 2023 functionality.
+
+As an example of this, we've added a new required question for schedule B that asks every taxpayer, "Do you have a foreign bank account?". Since that question is new and required, every person who submitted a tax return for 2023 now has an incomplete tax return against main. 
+
+We essentially have two options:
+1. We can build a new system where we maintain multiple versions of the flow, fact dictionary, mef, and pdf that support multiple tax years and scopes at one time. This is a lot of work to do.
+2. We can not worry about backcompatibility and block production users from accessing the flow/fact graph. We use generated PDFs to expose last year's answers to the user. We have to build a way to block users from accessing the flow in production, but don't need to maintain multiple versions of the app. There is still a consequence that users will never be able to re-open last year's tax return in the flow. 
+
+
+## Decision 
+- Next year, we will probably have to deal with multi-year support and multiple fact dictionaries/flows/etc. But this year, we're concentrating on expanding our tax scope to expand to more users. That is the priority, rather than providing a good read-experience for last year's 140k users.
+- We are ok to make non-backwards compatible changes. We can make changes that will break an existing user's fact graph. We will never try to open last year's users returns in a fact graph on main.
+- We're going to continue deploying 23.15 to prod through late June 2024, possibly into Q3 2024, until a point where:
+    - We have generated all existing users tax returns into PDFs
+    - We have a feature flagging method so that existing users in prod will be able to download their tax return as a PDF in prod
+    - Users in other test environments will be able to run with the new enhanced scope and we'll be building for next year. 
+
+There's additional product thought that needs to go through what the TY2024 app looks like for users who filed in TY2023 through Direct File.
+
+
+
+## Consequences
+- This means that we will need to apply security patches to 23.15 separately from main. We should probably also set it to build weekly/regularly.
+- Main is going to move ahead for TY2024. The next version of Direct File will always be the best one. 
+- We have work to do to put in a feature flag for last year's filers' experience in production so that those users will be able to download last year's tax return as a PDF.