Version Changelog

This document tracks major changes to the AQDx standard, including updates to the metadata schema, file formats, and documentation structure.

Version 3.0 (January 2025)

Focus: Machine Readability, Version Control, and Developer Experience.

The metadata submission process has been completely overhauled to support modern data engineering workflows.

Format Change: Switched from Excel (.xlsx) to YAML (.yaml).
- Why? YAML allows for nested structures (Instruments nested under Sites), is human-readable, and allows metadata to be tracked in version control systems like Git.
Schema Updates:
- Nesting: Instruments are no longer flat rows; they are now children of specific Site objects.
- Field Standardization: Field names in the metadata now exactly match the field names in the data files (e.g., data_steward_name is consistent across both).
- Data Quality: The "Quality Questionnaire" has been replaced by a structured data_quality object with boolean flags (automated_qc, corrections) and explicit description fields.

Migration to MkDocs: Documentation has moved from static PDFs to a live ReadTheDocs website generated from Markdown.
Searchability: Users can now search for specific field definitions or error codes instantly across the entire standard.
Versioning: Documentation is now versioned alongside the schema, allowing users to view guidance for previous versions if needed.

Parquet Support: Added Apache Parquet (.parquet) as a supported format for high-volume, archival datasets.