# What changed in openapi-fetch

> 4 changes in openapi-fetch 0.15 to 0.17 from its official release notes, upgrade guides and advisories: 1 new APIs and options. Each one cited. Sources checked 2026-10-18. HTML: https://unstale.sh/npm/openapi-fetch/

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

## openapi-fetch 0.17

### Behavior and default changes

- When generated types use read/write markers, openapi-fetch uses Readable<T> and Writable<T> to exclude readOnly properties from responses and writeOnly properties from request bodies. (0.17.0) — [release notes](https://github.com/openapi-ts/openapi-typescript/releases/tag/openapi-fetch%400.17.0)

### Fixes and other changes

- A Content-Length value of 0 is no longer treated as empty when Transfer-Encoding is chunked. (0.17.0) — [release notes](https://github.com/openapi-ts/openapi-typescript/releases/tag/openapi-fetch%400.17.0)

## openapi-fetch 0.16

### New APIs and options

- Set custom path serializers globally or per request to control how path parameters are serialized in the URL. (0.16.0) — [release notes](https://github.com/openapi-ts/openapi-typescript/releases/tag/openapi-fetch%400.16.0)

## openapi-fetch 0.15

### Fixes and other changes

- Uses text() when no content-length is provided to avoid errors parsing empty 200 responses. (0.15.2) — [release notes](https://github.com/openapi-ts/openapi-typescript/releases/tag/openapi-fetch%400.15.2)