Changelog

This changelog records customer-visible API contract changes. It does not disclose private tax-content acquisition, adjudication, infrastructure, or model implementation details.

1.4.0 — August 11, 2026

API 1.4 adds multi-location and supplemental-return workflows without changing existing v1 routes or API keys.

Added

• Effective-dated multi-location filing groups with versioned membership and per-location return detail.
• Colorado and Minnesota retail-delivery fee calculation and statewide return output, separate from sales tax.
• Purchase and reverse-charge use-tax return output for expected tax, vendor tax paid, use tax due, and overpayment review.
• Deterministic organization- or location-scoped mappings from Avalara and other caller taxability codes to ITMS tax codes.
• Washington B&O output for retailing, wholesaling, and explicit service-and-other rate tiers.
• California registered-location synchronization and Schedule C allocation with unmatched-site validation.

Compatibility and boundaries

• Existing direct tax_code requests remain compatible.
• Unmapped external tax codes fail closed; they are not passed to an AI fallback.
• Retail-delivery fees and B&O liabilities remain separate from buyer sales-tax totals.
• Purchase/use documents remain separate from ordinary sales-return gross and liability.
• Direct CDTFA getSubLocations extraction is not active pending Direct Transmitter certification and permanent state credentials. Verified CDTFA exports or reviewed location data can be synchronized now.
• Filing submission and money movement remain outside the customer API.

How to use this changelog

The endpoint reference and live OpenAPI contract remain the sources of truth for request and response shapes. Use GET /api/v1/coverage/states for current jurisdiction coverage. Routine tax-rate and content maintenance is not listed here unless it changes the customer contract or requires integration action.

Future deprecations will identify the replacement and sunset date. Existing v1 operations remain documented throughout their published notice period.