* Update example upgrade in docs main page. PR [#795](https://github.com/tiangolo/fastapi/pull/795) by [@cdeil](https://github.com/cdeil).
* Fix callback handling for sub-routers. PR [#792](https://github.com/tiangolo/fastapi/pull/792) by [@jekirl](https://github.com/jekirl).
* Fix typos. PR [#784](https://github.com/tiangolo/fastapi/pull/784) by [@kkinder](https://github.com/kkinder).
* Add 4 Japanese articles to [External Links](https://fastapi.tiangolo.com/external-links/). PR [#783](https://github.com/tiangolo/fastapi/pull/783) by [@HymanZHAN](https://github.com/HymanZHAN).