# What changed in moto

> 4 changes in moto 4 from its official release notes, upgrade guides and advisories: 2 breaking, 1 new APIs and options. Each one cited. Sources checked 2026-10-27. HTML: https://unstale.sh/pypi/moto/

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

## moto 4

### Breaking changes

- Removes the deprecated mock_dynamodb2 decorator. (4.0.0) — [release notes](https://github.com/getmoto/moto/blob/HEAD/CHANGELOG.md)
- Removes the deprecated mock_rds2 decorator. (4.0.0) — [release notes](https://github.com/getmoto/moto/blob/HEAD/CHANGELOG.md)

### New APIs and options

- Introduces MultiAccount support. (4.0.0) — [release notes](https://github.com/getmoto/moto/blob/HEAD/CHANGELOG.md)

### Behavior and default changes

- The API for the TreadedMotoServer is now considered stable. (4.0.0) — [release notes](https://github.com/getmoto/moto/blob/HEAD/CHANGELOG.md)