# What changed in sse-starlette

> 3 changes in sse-starlette 3 from its official release notes, upgrade guides and advisories: 1 breaking. Each one cited. Sources checked 2026-10-18. HTML: https://unstale.sh/pypi/sse-starlette/

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

## sse-starlette 3

### Breaking changes

- In the fallback path, sse-starlette no longer sets this when it detects uvicorn's Server.should_exit; streams still close on shutdown. Use shutdown_event to detect shutdown. (3.5.0) — [release notes](https://github.com/sysid/sse-starlette/releases/tag/v3.5.0)

### Fixes and other changes

- Stopping a uvicorn server no longer cancels SSE streams belonging to later servers in the same process. (3.5.0) — [release notes](https://github.com/sysid/sse-starlette/releases/tag/v3.5.0)
- The send timeout now also applies to heartbeat messages. (3.4.10) — [release notes](https://github.com/sysid/sse-starlette/releases/tag/v3.4.10)