Lifecycle timestamps. Required response properties archivedAt, completedAt, workflowCustomizedAt, and startedAt are null until that event occurs. Actual event timestamps are ISO date-time strings. This approved clarification supersedes the non-null types in the frozen OpenAPI download; request schemas are unchanged.

Dates, times, and timezones

Calendar dates use YYYY-MM-DD. Instants use RFC 3339 UTC, such as 2026-08-17T09:30:00Z. A local due time is interpreted with the user's configured timezone; it is not silently converted from the caller's locale.

Date-only arithmetic, weekly boundaries, working-day deadlines, and shipment-relative schedules follow workspace rules. Never send locale forms such as 17/08/2026. Derived order arrival and workflow deadlines are server results, not caller-authored audit values.