# What changed in @graphiql/plugin-explorer

> 10 changes in @graphiql/plugin-explorer 4 to 5 from its official release notes, upgrade guides and advisories: 5 breaking, 1 deprecations. Each one cited. Sources checked 2026-10-23. HTML: https://unstale.sh/npm/@graphiql/plugin-explorer/

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

## @graphiql/plugin-explorer 5

### Breaking changes

- When adding a custom plugin such as Explorer, explicitly include HISTORY_PLUGIN in the plugins array to keep the History plugin. (5.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-5.0.0.md)
- The UMD build is removed; use the ESM CDN example instead. (5.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-5.0.0.md)

### Behavior and default changes

- Comments are now supported in the Variables and Headers editors. (5.0.0) — [release notes](https://github.com/graphql/graphiql/releases/tag/%40graphiql/plugin-explorer%405.0.0)

### Tooling

- GraphiQL 5 is powered by the latest version of the Monaco editor. (5.0.0) — [release notes](https://github.com/graphql/graphiql/releases/tag/%40graphiql/plugin-explorer%405.0.0)

### Fixes and other changes

- Adds CSS files to sideEffects so CSS can be imported in Webpack JavaScript. (5.1.2) — [release notes](https://github.com/graphql/graphiql/releases/tag/%40graphiql/plugin-explorer%405.1.2)

## @graphiql/plugin-explorer 4

### Breaking changes

- CommonJS build output was dropped; the package now provides ESM output. (4.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-4.0.0.md)
- The style import path changed from @graphiql/plugin-explorer/dist/style.css to @graphiql/plugin-explorer/style.css. (4.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-4.0.0.md)
- Support for React 16/17 was dropped, and support for React 19 was added. (4.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-4.0.0.md)

### Deprecations

- The UMD build is deprecated; migrate to the ESM-based CDN. (4.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-4.0.0.md)

### Fixes and other changes

- Styles for the explorer UI were improved. (4.0.0) — [upgrade guide](https://github.com/graphql/graphiql/blob/main/docs/migration/graphiql-4.0.0.md)