# What changed in json-schema-to-pydantic

> 13 changes in json-schema-to-pydantic 0.4 from its official release notes, upgrade guides and advisories: 1 breaking, 5 new APIs and options. Each one cited. Sources checked 2026-10-20. HTML: https://unstale.sh/pypi/json-schema-to-pydantic/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## json-schema-to-pydantic 0.4

### Breaking changes

- The package now supports Python >=3.9. (0.4.5) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.5)

### New APIs and options

- Support predefined models when resolving $ref references. (0.4.10) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.10)
- Adds a parameter that allows models to be populated by either the original field name or the sanitized name. (0.4.9) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.9)
- Adds support for scalar roots. (0.4.8) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.8)
- Top-level array schemas are now supported using RootModel. (0.4.7) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.7)
- Adds allow_undefined_type to create_model. (0.4.6) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.6)

### Behavior and default changes

- Predefined refs now support non-model types. (0.4.11) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.11)
- JSON Schema fields starting with underscores are supported by stripping leading underscores from field names and creating aliases. (0.4.9) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.9)

### Fixes and other changes

- Properly handles underscore fields when using allOf combiners. (0.4.9) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.9)
- Properly handles underscore fields when using anyOf combiners. (0.4.9) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.9)
- Properly handles underscore fields when using oneOf combiners. (0.4.9) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.9)
- Fixes oneOf handling for simple types and references. (0.4.8) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.8)
- Support multiple type combinations in JSON Schema type arrays. (0.4.4) — [release notes](https://github.com/richard-gyiko/json-schema-to-pydantic/releases/tag/v0.4.4)