🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Security issues

urllib3 2.5.0 fixes two moderate security issues:

• Pool managers now properly control redirects when retries is passed — CVE-2025-50181 reported by @sandumjacob (5.3 Medium, GHSA-pq67-6m6q-mj2v)
• Redirects are now controlled by urllib3 in the Node.js runtime — CVE-2025-50182 (5.3 Medium, GHSA-48p4-8xcf-vxj5)

Features

• Added support for the compression.zstd module that is new in Python 3.14. See PEP 784 for more information. (#3610)
• Added support for version 0.5 of hatch-vcs (#3612)

Bugfixes

• Raised exception for HTTPResponse.shutdown on a connection already released to the pool. (#3581)
• Fixed incorrect CONNECT statement when using an IPv6 proxy with connection_from_host. Previously would not be wrapped in []. (#3615)

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Features

• Applied PEP 639 by specifying the license fields in pyproject.toml. (#3522)
• Updated exceptions to save and restore more properties during the pickle/serialization process. (#3567)
• Added verify_flags option to create_urllib3_context with a default of VERIFY_X509_PARTIAL_CHAIN and VERIFY_X509_STRICT for Python 3.13+. (#3571)

Bugfixes

• Fixed a bug with partial reads of streaming data in Emscripten. (#3555)

Misc

• Switched to uv for installing development dependecies. (#3550)
• Removed the multiple.intoto.jsonl asset from GitHub releases. Attestation of release files since v2.3.0 can be found on PyPI. (#3566)

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Features

• Added HTTPResponse.shutdown() to stop any ongoing or future reads for a specific response. It calls shutdown(SHUT_RD) on the underlying socket. This feature was sponsored by LaunchDarkly. (#2868)
• Added support for JavaScript Promise Integration on Emscripten. This enables more efficient WebAssembly requests and streaming, and makes it possible to use in Node.js if you launch it as node --experimental-wasm-stack-switching. (#3400)
• Added the proxy_is_tunneling property to HTTPConnection and HTTPSConnection. (#3285)
• Added pickling support to NewConnectionError and NameResolutionError. (#3480)

Bugfixes

• Fixed an issue in debug logs where the HTTP version was rendering as "HTTP/11" instead of "HTTP/1.1". (#3489)

Deprecations and Removals

• Removed support for Python 3.8. (#3492)

Full Changelog: 2.2.3...2.3.0

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Features

• Added support for Python 3.13. (#3473)

Bugfixes

• Fixed the default encoding of chunked request bodies to be UTF-8 instead of ISO-8859-1. All other methods of supplying a request body already use UTF-8 starting in urllib3 v2.0. (#3053)
• Fixed ResourceWarning on CONNECT with Python < 3.11.4 by backporting python/cpython#103472. (`#3252)
• Adjust tolerance for floating-point comparison on Windows to avoid flakiness in CI (#3413)
• Fixed a crash where certain standard library hash functions were absent in restricted environments. (#3432)
• Fixed mypy error when adding to HTTPConnection.default_socket_options. (#3448)

HTTP/2 (experimental)

HTTP/2 support is still in early development.

• Excluded Transfer-Encoding: chunked from HTTP/2 request body (#3425)
• Added version checking for h2 (https://pypi.org/project/h2/) usage. Now only accepting supported h2 major version 4.x.x. (#3290)
• Added a probing mechanism for determining whether a given target origin supports HTTP/2 via ALPN. (#3301)
• Add support for sending a request body with HTTP/2 (#3302)

Full Changelog: 2.2.2...2.2.3

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Changes

• Fixed a crash where certain standard library hash functions were absent in FIPS-compliant environments. (#3432)
• Replaced deprecated dash-separated setuptools entries in setup.cfg. (#3461)
• Took into account macOS setting ECONNRESET instead of EPROTOTYPE in its newer versions. (#3416)
• Backported changes to our tests and CI configuration from v2.x to support testing with CPython 3.12 and 3.13. (#3436)

Full Changelog: 1.26.19...1.26.20

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Changes

• Added the Proxy-Authorization header to the list of headers to strip from requests when redirecting to a different host. As before, different headers can be set via Retry.remove_headers_on_redirect.
• Allowed passing negative integers as amt to read methods of http.client.HTTPResponse as an alternative to None. (#3122)
• Fixed return types representing copying actions to use typing.Self. (#3363)

Full Changelog: 2.2.1...2.2.2

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Changes

• Added the Proxy-Authorization header to the list of headers to strip from requests when redirecting to a different host. As before, different headers can be set via Retry.remove_headers_on_redirect.

Full Changelog: 1.26.18...1.26.19

Note that due to an issue with our release automation, no multiple.intoto.jsonl file is available for this release.

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Changes

• Fixed issue where InsecureRequestWarning was emitted for HTTPS connections when using Emscripten. (#3331)
• Fixed HTTPConnectionPool.urlopen to stop automatically casting non-proxy headers to HTTPHeaderDict. This change was premature as it did not apply to proxy headers and HTTPHeaderDict does not handle byte header values correctly yet. (#3343)
• Changed ProtocolError to InvalidChunkLength when response terminates before the chunk length is sent. (#2860)
• Changed ProtocolError to be more verbose on incomplete reads with excess content. (#3261)

🖥️ urllib3 now works in the browser

🎉 This release adds experimental support for using urllib3 in the browser with Pyodide! 🎉

Thanks to Joe Marshall (@joemarshall) for contributing this feature. This change was possible thanks to work done in urllib3 v2.0 to detach our API from http.client. Please report all bugs to the urllib3 issue tracker.

🚀 urllib3 is fundraising for HTTP/2 support

urllib3 is raising ~$40,000 USD to release HTTP/2 support and ensure long-term sustainable maintenance of the project after a sharp decline in financial support for 2023. If your company or organization uses Python and would benefit from HTTP/2 support in Requests, pip, cloud SDKs, and thousands of other projects please consider contributing financially to ensure HTTP/2 support is developed sustainably and maintained for the long-haul.

Thank you for your support.

Changes

• Added support for Emscripten and Pyodide, including streaming support in cross-origin isolated browser environments where threading is enabled. (#2951)
• Added support for HTTPResponse.read1() method. (#3186)
• Added rudimentary support for HTTP/2. (#3284)
• Fixed issue where requests against urls with trailing dots were failing due to SSL errors
  when using proxy. (#2244)
• Fixed HTTPConnection.proxy_is_verified and HTTPSConnection.proxy_is_verified to be always set to a boolean after connecting to a proxy. It could be None in some cases previously. (#3130)
• Fixed an issue where headers passed in a request with json= would be mutated (#3203)
• Fixed HTTPSConnection.is_verified to be set to False when connecting from a HTTPS proxy to an HTTP target. It was set to True previously. (#3267)
• Fixed handling of new error message from OpenSSL 3.2.0 when configuring an HTTP proxy as HTTPS (#3268)
• Fixed TLS 1.3 post-handshake auth when the server certificate validation is disabled (#3325)

Note for downstream distributors: To run integration tests, you now need to run the tests a second time with the --integration pytest flag. (#3181)

Read the v2 migration guide for help upgrading to the latest version of urllib3.

Removals

• Removed support for the deprecated urllib3[secure] extra. (#2680)
• Removed support for the deprecated SecureTransport TLS implementation. (#2681)
• Removed support for the end-of-life Python 3.7. (#3143)

Bugfixes

• Allowed loading CA certificates from memory for proxies. (#3065)
• Fixed decoding Gzip-encoded responses which specified x-gzip content-encoding. (#3174)