Sourced from chardet's releases.

chardet 7.1.0

Features

• Added PEP 263 encoding declaration detection — # -*- coding: ... -*- and # coding=... declarations on lines 1–2 of Python source files are now recognized with confidence 0.95 (#249)
• Added chardet.universaldetector backward-compatibility stub so that from chardet.universaldetector import UniversalDetector works with a deprecation warning (#341)

Fixes

• Fixed false UTF-7 detection of ASCII text containing ++ or +word patterns (#332)
• Fixed 0.5s startup cost on first detect() call — model norms are now computed during loading instead of lazily iterating 21M entries (#333)
• Fixed undocumented encoding name changes between chardet 5.x and 7.0 — detect() now returns chardet 5.x-compatible names by default (#338)
• Improved ISO-2022-JP family detection — recognizes ESC sequences for ISO-2022-JP-2004 (JIS X 0213) and ISO-2022-JP-EXT (JIS X 0201 Kana)
• Fixed silent truncation of corrupt model data (iter_unpack yielded fewer tuples instead of raising)
• Fixed incorrect date in LICENSE

Performance

• 5.5x faster first-detect time (~0.42s → ~0.075s) by computing model norms as a side-product of load_models()
• ~40% faster model parsing via struct.iter_unpack for bulk entry extraction (eliminates ~305K individual unpack calls)

New API parameters

• Added compat_names parameter (default True) to detect(), detect_all(), and UniversalDetector — set to False to get raw Python codec names instead of chardet 5.x/6.x compatible display names
• Added prefer_superset parameter (default False) — remaps legacy ISO/subset encodings to their modern Windows/CP superset equivalents (e.g., ASCII → Windows-1252, ISO-8859-1 → Windows-1252). This will default to True in the next major version (8.0).
• Deprecated should_rename_legacy in favor of prefer_superset — a deprecation warning is emitted when used

Improvements

• Switched internal canonical encoding names to Python codec names (e.g., "utf-8" instead of "UTF-8"), with compat_names controlling the public output format
• Added lookup_encoding() to registry for case-insensitive resolution of arbitrary encoding name input to canonical names
• Achieved 100% line coverage across all source modules (+31 tests)
• Updated benchmark numbers: 98.2% encoding accuracy, 95.2% language accuracy on 2,510 test files
• Pinned test-data cloning to chardet release version tags for reproducible builds

Full changelog: https://chardet.readthedocs.io/en/latest/changelog.html

Sourced from chardet's changelog.

7.1.0 (2026-03-11)

Features:

• Added PEP 263 encoding declaration detection — # -*- coding: ... -*- and # coding=... declarations on lines 1–2 of Python source files are now recognized with confidence 0.95 (Dan Blanchard <https://github.com/dan-blanchard>, [#249](https://github.com/chardet/chardet/issues/249) <https://github.com/chardet/chardet/issues/249>)
• Added chardet.universaldetector backward-compatibility stub so that from chardet.universaldetector import UniversalDetector works with a deprecation warning (Dan Blanchard <https://github.com/dan-blanchard>, [#341](https://github.com/chardet/chardet/issues/341) <https://github.com/chardet/chardet/issues/341>)

Fixes:

• Fixed false UTF-7 detection of ASCII text containing ++ or +word patterns (Dan Blanchard <https://github.com/dan-blanchard>, [#332](https://github.com/chardet/chardet/issues/332) <https://github.com/chardet/chardet/issues/332>, [#335](https://github.com/chardet/chardet/issues/335) <https://github.com/chardet/chardet/pull/335>_)
• Fixed 0.5s startup cost on first detect() call — model norms are now computed during loading instead of lazily iterating 21M entries (Dan Blanchard <https://github.com/dan-blanchard>, [#333](https://github.com/chardet/chardet/issues/333) <https://github.com/chardet/chardet/issues/333>, [#336](https://github.com/chardet/chardet/issues/336) <https://github.com/chardet/chardet/pull/336>_)
• Fixed undocumented encoding name changes between chardet 5.x and 7.0 — detect() now returns chardet 5.x-compatible names by default (Dan Blanchard <https://github.com/dan-blanchard>, [#338](https://github.com/chardet/chardet/issues/338) <https://github.com/chardet/chardet/pull/338>)
• Improved ISO-2022-JP family detection — recognizes ESC sequences for ISO-2022-JP-2004 (JIS X 0213) and ISO-2022-JP-EXT (JIS X 0201 Kana) (Dan Blanchard <https://github.com/dan-blanchard>_)
• Fixed silent truncation of corrupt model data (iter_unpack yielded fewer tuples instead of raising) (Dan Blanchard <https://github.com/dan-blanchard>_)
• Fixed incorrect date in LICENSE (Dan Blanchard <https://github.com/dan-blanchard>_)

Performance:

• 5.5x faster first-detect time (~0.42s → ~0.075s) by computing model norms as a side-product of load_models() (Dan Blanchard <https://github.com/dan-blanchard>_)
• ~40% faster model parsing via struct.iter_unpack for bulk entry extraction (eliminates ~305K individual unpack calls) (Dan Blanchard <https://github.com/dan-blanchard>_)

... (truncated)

• f170eb4 perf: add early-exit check in PEP 263 detection for non-Python data
• 81dd662 refactor: use pathlib.Path instead of str for filesystem paths in scripts
• bf3ea5b test: achieve 100% test coverage
• ce5e991 fix: adjust benchmark speedup threshold for pure Python vs mypyc
• bfc8659 docs: update thread scaling table with GIL vs free-threaded benchmarks
• feff427 Remove plans that got thrown in other directory
• f854da5 fix: add --threads validation and docstring updates in compare_detectors.py
• 8029f87 fix: only include threads in timing cache keys, not memory cache keys
• cb3c71d feat: add --threads passthrough to compare_detectors.py
• d168ef0 feat: add --threads option to benchmark_time.py for concurrent detection
• Additional commits viewable in compare view

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