# What changed in jiter

> 12 changes in jiter 0.15 to 0.17 from its official release notes, upgrade guides and advisories: 2 breaking, 5 new APIs and options. Each one cited. Sources checked 2026-10-27. HTML: https://unstale.sh/pypi/jiter/

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

## jiter 0.17

### Breaking changes

- Python 3.9 support was dropped. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)

### New APIs and options

- Integer decoding was added to the x86_64 SIMD implementation. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)
- Adds reusable stacks for parsing values. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)

### Performance

- The Python string cache is locked once per parse rather than repeatedly. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)
- Empty and single-character strings now return CPython's singletons. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)
- Faster SIMD string scanning was added for non-ASCII characters and mask extraction on aarch64, and for string scanning on x86_64. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)
- SIMD string scanning was added for x86_64. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)

### Behavior and default changes

- Digit runs are used to determine whether a value should be decoded as a float or an integer. (0.17.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.17.0)

## jiter 0.16

### Breaking changes

- Support for the 3.13t target was dropped. (0.16.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.16.0)

### New APIs and options

- A serde Deserializer implementation was added. (0.16.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.16.0)

## jiter 0.15

### New APIs and options

- Exposes known_number_bytes for developers using the jiter API. (0.15.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.15.0)
- Exposes parser methods for converting bytes to numbers. (0.15.0) — [release notes](https://github.com/pydantic/jiter/releases/tag/v0.15.0)