# What changed in birpc

> 7 changes in birpc 4 from its official release notes, upgrade guides and advisories: 2 breaking, 3 new APIs and options. Each one cited. Sources checked 2026-10-19. HTML: https://unstale.sh/npm/birpc/

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

## birpc 4

### Breaking changes

- The unused /sse exports were removed and are now provided as an example receipt. (4.2.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.2.0)
- Deprecated APIs were removed. (4.0.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.0.0)

### New APIs and options

- Adds the client sub-export for the SSE + POST transport. (4.1.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.1.0)
- Adds the server sub-export for the SSE + POST transport. (4.1.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.1.0)
- An option was added to turn off proxification. (4.0.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.0.0)

### Fixes and other changes

- Fixes the return type for group. (4.1.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.1.0)
- Generic type checks were improved. (4.0.0) — [release notes](https://github.com/antfu-collective/birpc/releases/tag/v4.0.0)