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# Version History
(ngff-spec:history)=

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).

## [0.6.dev4] - 2026-04-22

### Changed

- BREAKING CHANGE: Unified `input` and `output` fields in all transformation metadata to be an object of `{"name": string, "path": string}` instead of allowing both string and object forms. This change was made to ensure consistency across all transformations and to simplify the specification.
- BREAKING CHANGE: Replaced `arrayCoordinateSystems` with explanation of how to properly express dimensionless transforms.
- style: Improved readability of multiscales section and `coordinates`/`displacements` transformations.

## [0.6.dev3] - 2026-03-13

### Changed

- Implemented feedback from Hackathon:
  - BREAKING CHANGE: Renamed top-level group for transformations to "Scene"
  - BREAKING CHANGE: Transformations in scene metadata must be object with fields "name" and "path"
  - BREAKING CHANGE: Made syntax of `mapAxis` and `byDimension` transforms consistent with other transforms
  - BREAKING CHANGE: Zarr parameter storage no longer allowed for scale/translation 
  - For detailed set of changes see [complete overview](https://ngff.openmicroscopy.org/rfc/5/responses/2/index.html)
- Updated version keys from `0.6.dev2` to `0.6.dev3` everywhere
- style: Homogeneous use of backticks in spec document
- specification: Changed the constraints for valid `path` values in `wells` for HCS plates to allow some non-alphanumeric characters.
- specification: Corrected that `version` field is not required under plate/well/labels metadata. 
- specification: Constrained datatype of multiscales datasets to be the same across all resolutions
- specification: Clarified that `name` field in `axes` metadata is required to be a non-empty string.
- style: Adopted JSON terminology for "object" and "array" in the spec document.

### Removed

- BREAKING CHANGE: Removed `inverseOf` transformation
- Removed `version` field from `multiscales` metadata in the image schema (`schemas/image.schema`) since it is already required at `ome > version`
- Removed `version` field from `plate`, `well` and `labels` metadata in the spec document since it is already required at `ome > version`.

## [0.6.dev2] - 2025-12-02

### Changed

Implemented feedback from [RFC-5 review 1 and 2](https://ngff.openmicroscopy.org/rfc/5/reviews/index.html)

## [0.6dev1] - 2025-11-18

### Added

Initial proposal for RFC-5: Transforms. [See proposal text](https://ngff.openmicroscopy.org/rfc/5/versions/1/index.html).

## [0.5.2] - 2025-01-10

### Changed

- Clarify that the `dimension_names` field in `axes` MUST be included.

## [0.5.1] - 2025-01-10

### Added

- Re-add the improved omero description in PR-191.

## [0.5.0] - 2024-11-21

### Changed

- use Zarr v3 in OME-Zarr, see [RFC-2](https://ngff.openmicroscopy.org/rfc/2).

## [0.4.1] - 2023-02-09

### Changed

- expand on "labels" description

## [0.4.1] - 2022-09-26

### Added

- transitional metadata for image collections ("bioformats2raw.layout")

## [0.4.0] - 2022-02-08

### Added

- multiscales: add axes type, units and coordinateTransformations
- plate: add rowIndex/columnIndex

## [0.3.0] - 2021-08-24

### Added

- Add axes field to multiscale metadata

## [0.2.0] - 2021-03-29

### Changed

- Change chunk dimension separator to "/"

## [0.1.4] - 2020-11-26

### Added

- Add HCS specification

## [0.1.3] - 2020-09-14

### Added

- Add labels specification

## [0.1.2] - 2020-05-07

### Added

- Add description of "omero" metadata

## [0.1.1] - 2020-05-06

### Added

- Add info on the ordering of resolutions

## [0.1.0] - 2020-04-20

First version for internal demo