# cffi: what changed from 1 to 2

- Product: cffi (https://whatsnew.fyi/product/cffi)
- Vendor: cffi
- Range: changelog entries numbered after v1.17.1 up to and including v2.1.1, stable releases only
- Entries below: 3 releases (newest first)
- Resolved: 1 is v1.17.1 and 2 is v2.1.1, the newest stable release of each major we track
- Carrying security changes: 0 · CVEs mentioned: 0 · Mentioning breaking changes: 0 · Removing or deprecating something: 2
- Page: https://whatsnew.fyi/product/cffi/compare/1...2

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

## What changed (12 changes, grouped by kind)

### Added

#### v2.1.0 (2026-07-06)

- Added support for Python 3.15 and support for C extensions generated by CFFI to target the new abi3t free-threaded ABI
- Added cffi-gen-src CLI to generate CFFI C extension source for alternate build backend support
- Added support for arm64 iOS wheels

#### v2.0.0 (2025-09-08)

- Add Python 3.14 support
- Add CPython free-threaded support (3.14t+ only)

### Fixed

#### v2.1.1 (2026-08-03)

- Minimize internal Python API usage for interpreter and thread state sampling to avoid breaking ABI change in Python >= 3.15.0b4

#### v2.1.0 (2026-07-06)

- Fixed crashes inside __delitem__
- Fixed string too big error under MSVC
- Fixed mingw builds

#### v2.0.0 (2025-09-08)

- Fix order dependency affecting nested type size calculation

### Removed

#### v2.1.0 (2026-07-06)

- Dropped support for Python 3.9

#### v2.0.0 (2025-09-08)

- Drop Python <= 3.8 support

## Release notes

### v2.1.1

- Date: 2026-08-03
- Version: v2.1.1
- Original notes: https://github.com/python-cffi/cffi/releases/tag/v2.1.1
- Permalink: https://whatsnew.fyi/product/cffi/releases/v2.1.1

- **fixed** — Minimize internal Python API usage for interpreter and thread state sampling to avoid breaking ABI change in Python >= 3.15.0b4

##### What's Changed
* Minimize internal Python API usage for interpreter and thread state sampling where possible. Avoids breaking ABI change in Python >= 3.15.0b4 (https://github.com/python-cffi/cffi/pull/269).


**Full Changelog**: https://github.com/python-cffi/cffi/compare/v2.1.0...v2.1.1

### v2.1.0

- Date: 2026-07-06
- Version: v2.1.0
- Original notes: https://github.com/python-cffi/cffi/releases/tag/v2.1.0
- Permalink: https://whatsnew.fyi/product/cffi/releases/v2.1.0

- **added** — Added support for Python 3.15 and support for C extensions generated by CFFI to target the new abi3t free-threaded ABI
- **removed** — Dropped support for Python 3.9
- **added** — Added cffi-gen-src CLI to generate CFFI C extension source for alternate build backend support
- **fixed** — Fixed crashes inside __delitem__
- **fixed** — Fixed string too big error under MSVC
- **fixed** — Fixed mingw builds
- **added** — Added support for arm64 iOS wheels

* Added support for Python 3.15 and support for C extensions generated by CFFI
  to target the new ``abi3t`` free-threaded ABI.
* Dropped support for Python 3.9.
* Added ``cffi-gen-src`` CLI to generate CFFI C extension source for alternate build backend support.
* Fixed crashes inside ``__delitem__``. 
* Fixed "string too big" error under MSVC.
* Fixed mingw builds.
* Added support for arm64 iOS wheels.

### v2.0.0

- Date: 2025-09-08
- Version: v2.0.0
- Original notes: https://github.com/python-cffi/cffi/releases/tag/v2.0.0
- Permalink: https://whatsnew.fyi/product/cffi/releases/v2.0.0

- **added** — Add Python 3.14 support
- **added** — Add CPython free-threaded support (3.14t+ only)
- **removed** — Drop Python <= 3.8 support
- **fixed** — Fix order dependency affecting nested type size calculation

##### What's Changed
* Add Python 3.14 support.
* Add CPython free-threaded support (3.14t+ only) - huge thanks to the folks at Quansight Labs for all the work to get this one sorted!
* Drop Python <= 3.8 support.
* Fix order dependency affecting nested type size calculation (#148).

**Full Changelog**: https://github.com/python-cffi/cffi/compare/v1.17.1...v2.0.0