# What changed in autoprefixer

> 16 changes in autoprefixer 10 from its official release notes, upgrade guides and advisories: 1 breaking, 3 new APIs and options. Each one cited. Sources checked 2026-10-17. HTML: https://unstale.sh/npm/autoprefixer/

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

## autoprefixer 10

### Breaking changes

- Removed the development key from package.json. (10.4.27) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.4.27)

### New APIs and options

- Added support for the initial-letter CSS property, allowing Autoprefixer to process it. (10.6.0) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.6.0)
- Added support for the mask-position-x CSS property. (10.5.0) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.0)
- Added support for the mask-position-y CSS property. (10.5.0) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.0)

### Performance

- Fixed performance of resolution media query parsing. (10.5.5) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.5)
- Package size was reduced, which may decrease installation or distribution overhead. (10.4.26) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.4.26)
- Autoprefixer is a little faster, reducing processing time for developers using it. (10.4.24) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.4.24)

### Fixes and other changes

- Fixed grid gap handling when set with the row-gap and column-gap longhands. (10.6.1) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.6.1)
- Fixed producing wrong old -webkit- gradients. (10.5.6) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.6)
- Fixed duplication of prefixed rules in generated CSS. (10.5.4) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.4)
- Fixed parsing of brackets in CSS. (10.5.3) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.3)
- Fixed gradient parsing in CSS. (10.5.3) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.3)
- Moved before -moz-available so Firefox uses the -webkit- version, which is closer to stretch. (10.5.2) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.2)
- Fixed span reset behavior when overriding grid areas. (10.5.1) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.5.1)
- Fixed broken gradients on CSS Custom Properties. (10.4.25) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.4.25)
- Fixed stretch prefixes using the new Can I Use database, improving generated CSS compatibility. (10.4.22) — [release notes](https://github.com/postcss/autoprefixer/releases/tag/10.4.22)