# What changed in @mui/system

> 11 changes in @mui/system 9 from its official release notes, upgrade guides and advisories: 6 breaking, 1 security, 1 new APIs and options. Each one cited. Sources checked 2026-10-20. HTML: https://unstale.sh/npm/@mui/system/

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

## @mui/system 9

### Breaking changes

- Grid no longer supports direction="column" or direction="column-reverse"; use Stack for vertical layouts. (9.0.0) — [upgrade guide](https://mui.com/system/migration/upgrade-to-v9)
- Removed from the theme components types; use the Grid component instead. (9.0.0) — [upgrade guide](https://next.mui.com/material-ui/migration/upgrade-to-v9)
- Removed from the theme components types; use global CSS with the `MuiTouchRipple-*` class names instead. (9.0.0) — [upgrade guide](https://next.mui.com/material-ui/migration/upgrade-to-v9)
- Run the system-props codemod on a folder to migrate deprecated system props. (9.0.0) — [upgrade guide](https://mui.com/system/migration/upgrade-to-v9)
- Deprecated system props were removed from Box, Grid, and Stack; use the sx prop for styling. (9.0.0) — [upgrade guide](https://mui.com/system/migration/upgrade-to-v9)
- Deprecated system props have been removed from Box, DialogContentText, Grid, Link, Stack, Typography, TimelineContent, and TimelineOppositeContent; move these styles into the sx prop. (9.0.0) — [upgrade guide](https://next.mui.com/material-ui/migration/upgrade-to-v9)

### Security

- Prevents prototype pollution in cssVarsParser. (9.3.0) — [release notes](https://github.com/mui/material-ui/blob/37894798e2bfc80c3d5b33c386e1c31147fba381/CHANGELOG.md#930)

### New APIs and options

- An opt-in augmentation enables data-* attributes on slot props. (9.2.0) — [release notes](https://github.com/mui/material-ui/blob/37894798e2bfc80c3d5b33c386e1c31147fba381/CHANGELOG.md#920)

### Fixes and other changes

- Fixes a script tag warning in Next.js 16 dev mode. (9.1.2) — [release notes](https://github.com/mui/material-ui/blob/37894798e2bfc80c3d5b33c386e1c31147fba381/CHANGELOG.md#912)
- Using responsive typography shorthand in sx no longer mutates the theme. (9.0.1) — [release notes](https://github.com/mui/material-ui/blob/37894798e2bfc80c3d5b33c386e1c31147fba381/CHANGELOG.md#901)
- Props like color are no longer consumed by the component instead of being forwarded to the element rendered via the component prop. (9.0.0) — [upgrade guide](https://mui.com/system/migration/upgrade-to-v9), [upgrade guide](https://next.mui.com/material-ui/migration/upgrade-to-v9)