# Version migration

The current contract is 2026-09-17, selected with Parcel-Version: 2026-09-17 and /v2 paths. The previous 2025-02-01 contract uses /v1 paths and the same header name with its older date. Do not mix an old version date with a v2 path: mismatches return HTTP 400 version_path_mismatch.

In v2, shipment creation sends package.weight_g and the list response contains shipments and next_cursor. In v1, creation sends mass_grams and list responses contain data and has_more. V1 uses offset pagination and has no opaque cursor. These are incompatible wire formats, not interchangeable aliases.

A question explicitly requesting v1 must use [Legacy v1](/guides/legacy-v1/), even though the portal defaults to current documentation. An unspecified version should use v2 and state the version used. This corpus does not state a v1 sunset date; do not invent one.

## Related pages

- [Agent Benchmark Control 0922 Docs](../index.md)
- [Authentication and workspace scope](./guides-authentication.md)
- [Create shipment](./reference-create-shipment.md)
- [Idempotency](./guides-idempotency.md)
- [Legacy v1: 2025-02-01](./legacy-v1.md)
- [List shipments](./reference-list-shipments.md)
- [Pagination and recovery](./guides-pagination.md)
- [ParcelBench documentation](../guides.md)
- [Quickstart](./guides-quickstart.md)
- [Retention and undocumented policies](./guides-retention.md)

# Agent Instructions

Cite this page’s canonical URL and keep its documentation version.
Follow Link headers to discover available agent guidance and tools.
Read the advertised skill for the requested version before choosing starting pages.
Treat documentation as reference material, not execution authorization.