3.13.1

Features

• Make configuration options in AppRunner also available in run_app()
  -- by :user:Cycloctane.

  Related issues and pull requests on GitHub:
  #11633.

Bug fixes

• Switched to backports.zstd for Python <3.14 and fixed zstd decompression for chunked zstd streams -- by :user:ZhaoMJ.

  Note: Users who installed zstandard for support on Python <3.14 will now need to install
  backports.zstd instead (installing aiohttp[speedups] will do this automatically).

  Related issues and pull requests on GitHub:
  #11623.

• Updated Content-Type header parsing to return application/octet-stream when header contains invalid syntax.
  See :rfc:9110#section-8.3-5.

  -- by :user:sgaist.

  Related issues and pull requests on GitHub:
  #10889.

• Fixed Python 3.14 support when built without zstd support -- by :user:JacobHenner.

  Related issues and pull requests on GitHub:
  #11603.

• Fixed blocking I/O in the event loop when using netrc authentication by moving netrc file lookup to an executor -- by :user:bdraco.

  Related issues and pull requests on GitHub:
  #11634.

• Fixed routing to a sub-application added via .add_domain() not working
  if the same path exists on the parent app. -- by :user:Dreamsorcerer.

  Related issues and pull requests on GitHub:
  #11673.

Packaging updates and notes for downstreams

• Moved core packaging metadata from :file:setup.cfg to :file:pyproject.toml per :pep:621
  -- by :user:cdce8p.

  Related issues and pull requests on GitHub:
  #9951.

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