Future Tax Years
How to prepare the KB and engine for TY2026 and later.
Rollover Pattern
Future years should get a new rules file, a new article, and targeted golden vectors. Avoid editing a prior-year rules file unless correcting that year.
First Things To Add
- Official source links for the year.
- Differences from TY2025 that affect source fields or diagnostics.
- Migration notes for seeded fixtures and manual-entry forms.
- A short compatibility note for any changed form names or line mappings.