* Upgrade required Starlette to `0.12.9`, the new range is `>=0.12.9,<=0.12.9`.
* Add `State` to FastAPI apps at `app.state`.
* PR [593](https://github.com/tiangolo/fastapi/pull/593).
* Improve handling of custom classes for `Request`s and `APIRoute`s.
* This helps to more easily solve use cases like:
* Reading a body before and/or after a request (equivalent to a middleware).
* Run middleware-like code only for a subset of *path operations*.
* Process a request before passing it to a *path operation function*. E.g. decompressing, deserializing, etc.
* Processing a response after being generated by *path operation functions* but before returning it. E.g. adding custom headers, logging, adding extra metadata.
* New docs section: [Custom Request and APIRoute class](https://fastapi.tiangolo.com/tutorial/custom-request-and-route/).
* PR [589](https://github.com/tiangolo/fastapi/pull/589) by [dmontagu](https://github.com/dmontagu).
* Fix preserving custom route class in routers when including other sub-routers. PR [538](https://github.com/tiangolo/fastapi/pull/538) by [dmontagu](https://github.com/dmontagu).