# What changed in jsonpack

> 5 changes in jsonpack 2 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/npm/jsonpack/

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

## jsonpack 2

### Breaking changes

- AMD compatibility was dropped. (2.0.0) — [release notes](https://github.com/rgcl/jsonpack/releases/tag/v2.0.0)
- IE8 compatibility was dropped. (2.0.0) — [release notes](https://github.com/rgcl/jsonpack/releases/tag/v2.0.0)

### New APIs and options

- The package now has dual CommonJS and ES module output. (2.0.0) — [release notes](https://github.com/rgcl/jsonpack/releases/tag/v2.0.0)

### Performance

- Packing performance was improved. (2.0.0) — [release notes](https://github.com/rgcl/jsonpack/releases/tag/v2.0.0)

### Fixes and other changes

- Array detection is now checked properly. (2.0.0) — [release notes](https://github.com/rgcl/jsonpack/releases/tag/v2.0.0)