Bump uvicorn from 0.48.0 to 0.53.0

[dependabot]

Bumps uvicorn from 0.48.0 to 0.53.0.

Release notes

Sourced from uvicorn's releases.

Version 0.53.0

🌐 Opt-in HTTP/2 support

uvicorn 0.53.0 adds experimental HTTP/2 through zttp, alongside a new zuvloop integration and connection-handling improvements.

uv add uvicorn==0.53.0

• Serve HTTP/1.1 and HTTP/2 with zttp (#2982, #3101). Install zttp, then enable HTTP/2 with --http zttp --http2. Uvicorn negotiates HTTP/2 over TLS with ALPN and supports cleartext prior knowledge.
• HTTP/2 remains experimental. Upgrade-based h2c and WebSockets over HTTP/2 are not supported.

⚙️ More event loop choice

• Run Uvicorn with zuvloop (#3104). Install zuvloop separately and select it explicitly with --loop zuvloop on CPython 3.14 or newer.

🛡️ More reliable connections and proxies

• Honor Connection: close token lists (#3103). Uvicorn now parses comma-separated tokens case-insensitively across HTTP implementations.
• Trust IPv6 loopback proxies by default (#3119). The default FORWARDED_ALLOW_IPS value now includes ::1.
• Keep upgraded WebSockets alive (#3107). Uvicorn cancels the HTTP keep-alive timer when the connection becomes a WebSocket.

Full changelog: 0.52.4...0.53.0

Version 0.52.4

Fixed

• Remove duplicate Date headers from accepted WebSocket handshakes with websockets-sansio (#3078)

Full Changelog: Kludex/uvicorn@0.52.3...0.52.4

Version 0.52.3

Changed

• Update zttp to 0.0.24 and use its combined receive path, improving HTTP/1.1 request parsing performance (#3067)

Full Changelog: Kludex/uvicorn@0.52.2...0.52.3

Version 0.52.2

Fixed

• Update zttp to 0.0.22, fixing bodyless request receives and improving HTTP/1 request parsing performance (#3063)

Full Changelog: Kludex/uvicorn@0.52.1...0.52.2

Version 0.52.1

Fixed

• Complete the closing handshake on server-initiated WebSocket closes in the websockets-sansio and wsproto implementations, waiting for the client's close reply with a 10 second timeout instead of resetting the connection (#3053)
• Add missing write flow control to the websockets-sansio implementation, preventing data truncation on server-initiated closes with large in-flight payloads (#3048)

... (truncated)

Changelog

Sourced from uvicorn's changelog.

0.53.0 (September 14, 2026)

This release adds experimental HTTP/2 support through zttp. Enable it with --http zttp --http2. Upgrade-based h2c and WebSockets over HTTP/2 are not supported.

Added

• Add experimental HTTP/2 support through zttp (#2982, #3101)
• Add support for zuvloop (#3104)

Fixed

• Handle comma-separated, case-insensitive Connection: close tokens across HTTP implementations (#3103)
• Trust IPv6 loopback in the default FORWARDED_ALLOW_IPS value (#3119)
• Cancel the HTTP keep-alive timer when upgrading to WebSocket (#3107)

0.52.4 (August 18, 2026)

Fixed

• Remove duplicate Date headers from accepted WebSocket handshakes with websockets-sansio (#3078)

0.52.3 (August 13, 2026)

Changed

• Update zttp to 0.0.24 and use its combined receive path, improving HTTP/1.1 request parsing performance (#3067)

0.52.2 (August 13, 2026)

Fixed

• Update zttp to 0.0.22, fixing bodyless request receives and improving HTTP/1 request parsing performance (#3063)

0.52.1 (August 1, 2026)

Fixed

• Complete the closing handshake on server-initiated WebSocket closes in the websockets-sansio and wsproto implementations, waiting for the client's close reply with a 10 second timeout instead of resetting the connection (#3053)
• Add missing write flow control to the websockets-sansio implementation, preventing data truncation on server-initiated closes with large in-flight payloads (#3048)
• Handle connection loss while a WebSocket write is waiting on backpressure (#3050)
• Remove duplicate Content-Type and Content-Length headers from WebSocket denial responses on the websockets-sansio implementation, and deliver non-UTF-8 denial bodies intact (#3041)

0.52.0 (July 29, 2026)

This release adds an experimental HTTP/1.1 implementation backed by zttp, a sans-IO HTTP parser I've been developing on the side: a core written in Zig, with bindings to Python. It has been running under a fuzzer for some weeks now, and has been through multiple rounds of security auditing.

It is still experimental, so don't put it in front of production traffic yet. Try it with --http zttp, and please send any feedback to the issue tracker.

Added

... (truncated)

Commits

• 421708f Version 0.53.0 (#3136)
• f1a1bff Unset the keep-alive timer when upgrading to WebSocket (#3107)
• 63971ed Document HTTP/2 support (#3130)
• 7d1a005 Remove race from multiprocess health check test (#3128)
• 5ac6265 Add ::1 to FORWARDED_ALLOW_IPS (#3119)
• 098b206 Remove timing race from SIGHUP supervisor test (#3127)
• 968f15e chore(deps): bump the github-actions group with 4 updates (#3113)
• 7d4c08c chore(deps): bump the python-packages group across 1 directory with 11 update...
• fe528a4 Require explicit opt-in for zttp HTTP/2 (#3101)
• fa324a4 chore(deps-dev): bump httpx2 from 2.10.0 to 2.12.0 (#3121)
• Additional commits viewable in compare view

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