3.5.2 (2026-09-29)

Changed

• Raised the Cython upper bound to <3.4 for native builds. The bound remains <3.3 for
  abi3 builds to preserve compatibility with the Python 3.7 Limited API.

Fixed

• Valid UTF-8 Chinese JSON incorrectly detected as PTCP154 due to excessive noise penalties
  for uncommon CJK characters. (#796)
• Supported encodings without aliases failing name resolution or being ignored in charset
  declarations. (#800)

3.5.1 (2026-08-15)

Changed

• Raised upper bound of setuptools to v84 (#794)
• Cache performance access optimization for our CharInfo struct (prebuilt only).

Fixed

• No longer decoding large content when the noise detector output give a high entropy.
  Only impacted large content input >1M bytes.

3.5.0 (2026-08-12)

Added

• Explicit support for Python 3.15

Fixed

• Comparing a CharsetMatch to a non-alias encoding strings (#773)
• Return 0.0 CharsetMatch.multi_byte_usage for empty payloads instead of crashing (#774)
• A file with both a charset declaration and BOM/SIG did not verify first the BOM/SIG charset.
• iso2022* cases misdetected due to a flaw in our multibyte chunking logic.

Changed

• Replaced the optional mypyc build with Cython extensions while retaining the
  pure Python fallback. The previous engine (mypyc) started to hit rough limit around
  the optimization of our noise/coherence detector while Cython allows us to
  steer the engine toward the right generated optimized sources.
  This change SHOULD not impact bundler (e.g. Pyinstaller) as the module are
  immediately discoverable (i.e. not hidden import like mypyc did).
  Moreover, a long wished distribution is the abi3 wheels, this will allow us
  to no longer rush each year when a new Python interpreter is released.
  We still distribute the interpreter specific wheels for faster performance.
• Applied micro-optimization on several utils.
• CharsetMatches no longer sort on each match insertion.

Misc

• Removed an old performance optimization attempt in apy.py (success_fast_tracked+payload_result_cache).

3.4.9 (2026-07-07)

Fixed

• Regression in our fallback path leading to a decode error. (#771)
  We've yanked 3.4.8 as a result of that bug.

3.4.8 (2026-07-06)

Fixed

• Wall import time due to cascade codec imports for our multibyte first sort of iana supported codecs (#742)
• Unnecessary json import at runtime (#753)
• Inverse capitalization not seen by noise detector (#731)

Changed

• No longer holding a global cache for our noise / coherence measurements. Relax RSS memory usage.
• Micro-optimizations in our noise / coherence measurements.
• No longer using regex search by default for our preemptive charset mark algorithm.
• Raised upperbound of setuptools to v83.
• Raised upperbound of mypy(c) to v2.1.

Removed

• Redundant UTF7 BOM marker (#730)

3.4.7 (2026-04-02)

Changed

• Pre-built optimized version using mypy[c] v1.20.
• Relax setuptools constraint to setuptools>=68,<82.1.

Fixed

• Correctly remove SIG remnant in utf-7 decoded string. (#718) (#716)

3.4.6 (2026-03-15)

Changed

• Flattened the logic in charset_normalizer.md for higher performance. Removed eligible(..) and feed(...)
  in favor of feed_info(...).
• Raised upper bound for mypy[c] to 1.20, for our optimized version.
• Updated UNICODE_RANGES_COMBINED using Unicode blocks v17.

Fixed

• Edge case where noise difference between two candidates can be almost insignificant. (#672)
• CLI --normalize writing to wrong path when passing multiple files in. (#702)

Misc

• Freethreaded pre-built wheels now shipped in PyPI starting with 3.14t. (#616)

3.4.5 (2026-03-06)

Changed

• Update setuptools constraint to setuptools>=68,<=82.
• Raised upper bound of mypyc for the optional pre-built extension to v1.19.1

Fixed

• Add explicit link to lib math in our optimized build. (#692)
• Logger level not restored correctly for empty byte sequences. (#701)
• TypeError when passing bytearray to from_bytes. (#703)

Misc

• Applied safe micro-optimizations in both our noise detector and language detector.
• Rewrote the query_yes_no function (inside CLI) to avoid using ambiguous licensed code.
• Added cd.py submodule into mypyc optional compilation to reduce further the performance impact.

3.4.4 (2025-10-13)

Changed

• Bound setuptools to a specific constraint setuptools>=68,<=81.
• Raised upper bound of mypyc for the optional pre-built extension to v1.18.2

Removed

• setuptools-scm as a build dependency.

Misc

• Enforced hashes in dev-requirements.txt and created ci-requirements.txt for security purposes.
• Additional pre-built wheels for riscv64, s390x, and armv7l architectures.
• Restore multiple.intoto.jsonl in GitHub releases in addition to individual attestation file per wheel.

3.4.3 (2025-08-09)

Changed

• mypy(c) is no longer a required dependency at build time if CHARSET_NORMALIZER_USE_MYPYC isn't set to 1. (#595) (#583)
• automatically lower confidence on small bytes samples that are not Unicode in detect output legacy function. (#391)

Added

• Custom build backend to overcome inability to mark mypy as an optional dependency in the build phase.
• Support for Python 3.14

Fixed

• sdist archive contained useless directories.
• automatically fallback on valid UTF-16 or UTF-32 even if the md says it's noisy. (#633)

Misc

• SBOM are automatically published to the relevant GitHub release to comply with regulatory changes.
  Each published wheel comes with its SBOM. We choose CycloneDX as the format.
• Prebuilt optimized wheel are no longer distributed by default for CPython 3.7 due to a change in cibuildwheel.