Migration — Staying Current

Paxman follows Semantic Versioning. The capability set, the contract surface, and the data tables grow across releases — your code should be ready to move forward without surprise.

In plain language: small releases add things; breaking releases can change things. This page tells you which is which and what to do when you upgrade.

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Versioning

Version bump	Meaning for your code	Example
PATCH (0.0.X)	Contract compatibility preserved. Docs and internal fixes; authority data corrections may change recognition, status, or canonicalized_value when specs evolve — re-run golden samples even on PATCH.	0.1.0 → 0.1.1 may update CLDR/IDNA tables
MINOR (0.X.0)	Contract compatibility preserved (existing contracts still validate). Data-driven results may change when authority tables grow — pin paxman version and use contract.year (filters publication_year <= year) where point-in-time reproducibility matters, store version_stamp, and re-run golden samples.	0.1.x → 0.2.0 adds capabilities and data
MAJOR (X.0.0)	Breaking contract or flag semantics. Read the release notes — names, defaults, or canonical forms may change.	0.x → 1.0.0

Contract compatibility (which contracts are accepted) is stable across PATCH and MINOR; result stability (which status/canonicalized_value you get) depends on data and is not promised when spec tables change. year filters rules by publication_year <= year; only pinned_rules and excluded_rules identify rules. Provenance and spec-version changes alone do not imply a MAJOR bump.

Determinism is per-installed-build: the version_stamp.paxman_version on every ExecutionResult records exactly which build produced the answer, so you can audit what changed across an upgrade. Since 0.2.0, version_stamp.recognition_revision (hash of the compiled matcher set + snapshot SHAs, per ADR-0009 §13) is the same-snapshot diff signal — if recognition_revision changes, recognition behavior changed for at least one capability even when paxman_version is unchanged (e.g., a lexicon token table update).

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0.3.2 — ISBN/ISSN audit + kernel label fix (patch, non-breaking)

Scope: patch 0.3.1 → 0.3.2 — contract compatibility preserved, no new capability, no flag change. Two audit truncation guards plus one kernel span fix; docs now cover ISSN as a first-class page.

What changed:

Area	Before (0.3.1)	After (0.3.2)
ISBN truncated hyphen continuation (1 0-306-40615-2, cut 978-… groups)	matched a truncated prefix	rejected → MISSING (trailing (?![-]\d) guard, both grammars)
ISSN truncated hyphen-digit (0317-8471-2)	matched truncated 0317-8471	rejected → MISSING (same guard class)
IBAN bare-colon label (IBAN:AA0000000000000 after other text)	span covered core only (31, 46) — new/legacy parity gap	span absorbs label (26, 46, 'IBAN:AA0000000000000'), matching legacy
ISBN helpers	_find_length duplicated in capability + rule	single find_registrant_length in rules/data/range_message.py (+ alias) — no behavior change
Docs	no docs/user/capabilities/issn.md	ISSN user page added; ISBN recognition-vs-validation table clarified

Why this is correct: truncated prefixes are not valid identifiers (ISO 2108 / ISO 3297 check structure), so MISSING beats a truncated SUCCESS; the IBAN label belongs to the mention per the frozen legacy reference. normalize() now honors “Rules never raise” on direct calls for the touched ISBN rules.

How to detect: result.version_stamp.paxman_version 0.3.2 vs 0.3.1; recognition_revision bumps for the new trailing guards and the LabelMatcher scan change.

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0.3.1 — IP audit fixes (patch, non-breaking)

Scope: patch 0.3.0 → 0.3.1 — contract compatibility preserved, no new capability, no flag change. One grammar completeness fix plus defensive hardening; docs now surface the new behavior.

What changed:

Area	Before (0.3.0)	After (0.3.1)
IPv6 mixed with embedded IPv4 (::ffff:192.0.2.1, 64:ff9b::192.0.2.1, ::192.0.2.1)	truncated to ::ffff:192 + second candidate 192.0.2.1 → AMBIGUOUS ['::ffff:192','192.0.2.1'] (truncated value)	single IPv6 candidate ::ffff:192.0.2.1 (plus trailing 192.0.2.1 via IPv4 \b) → AMBIGUOUS ['::ffff:192.0.2.1','192.0.2.1'] — prefer the IPv6 value (overlap documented, cross-grammar dedup deferred without ADR)
IPv4 leading-zero (010.020.030.040)	recognized and normalized to 10.20.30.40 (already) — now documented	same, documented in docs/user/capabilities/ip.md and README.md
IPNotation	@dataclass(frozen=True)	@dataclass(frozen=True, slots=True) + field docs — no behavior change
normalize()	raised ValueError/AddressValueError on 999.999.999.999 / not-an-ip	try/except ValueError → returns input unchanged (never raises)
Provenance URLs	https://tools.ietf.org/html/rfc791	https://datatracker.ietf.org/doc/html/rfc791 (same for RFC 5952)
Docs	IP page listed only compressed/expanded IPv6	now lists mixed LS32 (RFC 4291 §2.2), leading-zero, overlap and triple-colon notes

Why this is correct: 0.3.0 under-recognized Las32 mixed addresses that ipaddress.IPv6Address already accepts and RFC 4291 defines; 0.3.1 aligns recognition with the validated spec. The overlapping 192.0.2.1 candidate remains until an engine cross-grammar dedup policy exists — callers should pick the IPv6 value (see docs/user/capabilities/ip.md overlap note). normalize() now honors “Rules never raise” even on direct calls.

How to detect: result.version_stamp.paxman_version 0.3.1 vs 0.3.0; recognition_revision also bumps for the new mixed branches.

Migration snippet:

from paxman.api.bootstrap import register_all_shipped
from paxman.api import canonicalize
from paxman.capabilities.IP.contract import IPContract

register_all_shipped()
r = canonicalize("::ffff:192.0.2.1", IPContract())
# 0.3.0: AMBIGUOUS ['::ffff:192', '192.0.2.1']  (truncated)
# 0.3.1: AMBIGUOUS ['::ffff:192.0.2.1', '192.0.2.1']  (correct, prefer IPv6)
assert r.status.value == "ambiguous"
assert r.candidates[0].value == "::ffff:192.0.2.1"

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0.2.0 — Recognition Kernel (breaking, scoped)

Scope: This is a pre-1.0 minor bump (0.1.0 → 0.2.0) with one intentional breaking change: the F1 correctness fix for whole-input vocabulary matching (ADR-0009). All other inputs are byte-identical under the parity gate.

What changed: Country name_recognition moved from whole-input lookup to an in-text word-anchored trie on the CountryNameFold view. Short-code grammars (alpha2) now honestly compete with the name grammar instead of silently winning when the name was invisible.

Input class	Before (0.1.x pipeline)	After (0.2.0 kernel)
Exact name, whole input ("United States")	SUCCESS "US"	SUCCESS "US" — unchanged
Name embedded in prose ("Ship to United States please")	SUCCESS "TO" — wrong (Tonga)	MultipleMentionsError under a single_value contract; both mentions via paxman.scan()
Short code as ordinary word ("to" in prose)	recognized and validated as alpha-2 — silent win	recognized; competes with the name mention — no silent win
All other inputs	—	byte-identical (parity gate)

Migration snippet:

# Exact value — unchanged:
import paxman
from paxman.capabilities.Country import Country

paxman.register_all_shipped()
contract = Country.create_contract()
paxman.canonicalize("United States", contract)  # SUCCESS "US"

# Prose with embedded values — the new honest paths:
from paxman.core.errors import MultipleMentionsError

try:
    result = paxman.canonicalize("Ship to United States please", contract)
except MultipleMentionsError:
    # scan() shares one ScanContext substrate across all contracts in the batch
    mentions = paxman.scan("Ship to United States please", [contract])
    # mentions.mentions["country"] == [
    #   Mention(span=(5, 7), grammar="alpha2_recognition", notation=...),
    #   Mention(span=(8, 21), grammar="name_recognition", notation=...),
    # ]
    # Segment first — docs/recipes/segmentation.md remains valid
    for m in mentions.mentions["country"]:
        print(m.span, m.grammar, m.notation)

# Or segment-first (recipe) — `paxman.scan` is preferred; no direct
# `normalize_name` import is needed.

How to detect the change: Compare result.version_stamp.recognition_revision across builds. The F1 migration changes the compiled matcher set, so recognition_revision changes even if you stay on the same paxman_version snapshot. Store both paxman_version and recognition_revision for audit trails.

Why this is correct: 0.1.x returned a confident, provenance-backed, wrong answer on ordinary prose ("Ship to United States please" → Tonga). 0.2.0 surfaces the competition honestly; scan() turns the caller-owned split-then-canonicalize loop into an API (see docs/recipes/segmentation.md and paxman scan --help).

Other 0.2.0 additions (non-breaking):

• paxman.scan(text, contracts) batch API + Mention/ScanResult model + paxman scan CLI (one substrate pass, see docs/user/api-reference.md).
• ScanContext lazy views, MatcherSpec/LexiconMatcher trie (SIUnit 2.4–6.5× win at 650/820 tokens), BoundarySpec presets, AnchorSet T0 prefilter.
• Snapshot rails (paxman/shared_data/*_snapshot.json + tools/regenerate_* + CI drift gate) and derived recognition keys (BIC country codes, Language IANA subset) per ADR-0009 §14.

0.2.0 — Two-array offset maps (A4 Rev.4, breaking in spans only)

Pre-0.2.0 the recognition kernel used a single-array D3 invariant offsets[s] -> offsets[e] with a len(text) sentinel. When a normalizer dropped source characters (CountryNameFold strips punctuation, StripSeparators drops ()-., IDNAFold drops tabs) the translated end absorbed the dropped tail: "United States." recognized as (0, 14) with raw_text == "United States.". ADR-0009 Rev.4 amends D3 to two arrays:

View.original_span(s, e) -> (starts[s], ends[e-1]) when mapped, (s, e) when None; empty (0, 0). Each normalizer now returns (subject, starts, ends) with len(starts)==len(ends)==len(subject) and 0 <= starts[i] < ends[i] <= len(text).

Visible change (Option 1, word-boundary-aligned mentions):

Input	Before	After
"United States." name mention	(0, 14) raw_text="United States."	(0, 13) raw_text="United States"
"United States of America,"	(0, 25) includes trailing ,	(0, 24) trimmed
"+1 (555) 123-4567" via StripSeparators	ends[-1]==len(text) sentinel	ends per-char s+1, original_span(0,n)==(0,17) exact
All length-preserving views (CaseFold etc.)	None	None, None — zero-cost unchanged

Whole-input canonical values are unchanged (rules normalize); only span/raw_text presentation shifts, and scan() mentions no longer carry trailing dropped punctuation. raw_text == text[start:end] is now an engine invariant enforced for every emitted match.

Migrate: if you stored span for later slicing, re-derive it from the new ExecutionResult.span/Mention.span; do not add +1 for dropped chars. Golden samples that asserted (0, 14) for "United States." should assert (0, 13).

0.4.0 — Whole-input suppression exemption (A0, #122)

Calling canonicalize() with a contract asserts the kind — “a canonical value is derivable from this input” — so suppressing the whole input contradicted the asserted intent (MISSING indistinguishable from canonicalize("")). Under suppress_common_words=True, a suppressible word-bounded hit that covers the entire trimmed input is now never suppressed (ADR-0009 Rev.5, §16 amendment). Embedded mentions stay suppressed — scan() prose behavior is unchanged.

Behavior change (only under suppress_common_words=True; flag-off results are byte-identical):

Input	Contract	Before (0.2.0–0.3.x)	After (0.4.0)
to / TO / to	Country, suppress on	MISSING	SUCCESS "TO"
ALL	Currency, suppress on	MISSING	SUCCESS "ALL"
en	Language, suppress on	MISSING	SUCCESS "en"
in/	Country, suppress on	MISSING	MISSING (only the whole input is exempt), suppressed_count=1
to and usa	Country, suppress on	SUCCESS "US"	unchanged (embedded to/and and the α3 usa hit stay suppressed — usa ∈ COMMON_WORDS; survival is via the non-suppressible name_recognition hit at the same span)
cd	SIUnit, suppress on	SUCCESS "cd"	unchanged (no SIUnit matcher is suppressible)

This supersedes the whole-input row of the 0.2.0 suppression note below (canonicalize("to", … suppress on) → MISSING no longer holds); the rest of that note (table, matchers, scan guidance) still applies.

New ExecutionResult signal — suppressed_count: int = 0 and suppressed_spans: tuple[tuple[int, int], ...] = (), populated whenever suppression fires (on MISSING and INVALID, not just MISSING; 0/() when the flag is off), so MISSING + suppressed_count == 1 (“recognized but suppressed”) is distinguishable from MISSING + suppressed_count == 0 (“nothing recognized”):

result = paxman.canonicalize("in/", Country.create_contract(suppress_common_words=True))
assert result.status == Resolution.MISSING
assert result.suppressed_count == 1
assert result.suppressed_spans == ((0, 2),)

A1 rejected: the x→0 fallback (keep the unsuppressed set when suppression would leave zero mentions, e.g. "to and is") is evaluated and rejected in #122 — suppression-to-MISSING there is the desired noise reduction, now observable via the signal instead of silent.

Migrate: if you worked around whole-input suppression (flag-off contracts for bare codes, special-casing MISSING for to/ALL/en), you can drop the workaround and pass the suppression contract straight through — whole-input canonical values now re-enter as fixed points under suppression (ADR-0010 property suite, #123 cross-link). See ADR-0009 Rev.5.

0.4.0 — Phone national de-offered, split successor (breaking, ADR-0011 Phase 2)

PhoneContract(output_format="national") now raises ContractError with a migration message naming split (was SUCCESS rendering the bare NSN for NANP values, E.164 otherwise). national dropped the country code that recognition/validation depend on and could not re-enter under the default contract (param dependence; value-dependent shape).

Before (0.3.x)	After (0.4.0)
Phone.create_contract(output_format="national") → SUCCESS "2125551234"	raises ContractError (migrate to split)
Phone.create_contract(output_format="split") → ContractError	SUCCESS "+1 2125551234" (uniform +CC NSN, param-free re-entry)

Migrate: replace output_format="national" with output_format="split" for storage and round-tripping; e164/rfc3966 unchanged; default_country remains input-only for national-shaped input.

0.4.0 — Language alpha2 carries subtags (changed, ADR-0011 Phase 3)

alpha2 now maps the primary subtag and carries the remainder verbatim (en-US → en-US, was en). alpha3/alpha3-bib render the primary only for extended tags (de-CH-1901 → deu/ger) and stay waived projections that re-enter as fixed points. Bare-code rendering unchanged.

Migrate: if you asserted alpha2 strips subtags, update goldens to the carried form; use name only for display (waived projection).

0.4.0 — MacAddress bit_reversed de-offered (breaking, ADR-0010)

MacAddressContract(output_format="bit_reversed") now raises ContractError (was per-octet bit-swap SUCCESS). The view is an involution (f(f(x)) == x), not a fixed point, so it is no longer offered.

Migrate: use default colon for storage; compute Token-Ring display locally.

0.4.0 — New capabilities: Element + Coordinates (additive)

Element (IUPAC symbol canonical, name format) and Coordinates (lat-first decimal canonical, decimal/iso6709/geo_uri/geojson_pair/dms/dm formats) are registered by register_all_shipped() (now 18 shipped). MacAddress registration is also activated. No migration required — existing contracts are byte-identical.

0.2.0 — Common-word suppression for scan (B1, ADR-0009 §16)

ADR-0009 §16 was deferred as non-binding; it now ships off by default as the suppression table for usable scan() on prose (R7: ~80% of prose scan() hits were short-code noise like to→Tonga). The change is additive and off-by-default — byte-identical for every existing caller.

Contract: CapabilityContract.suppress_common_words: bool = False (after extra_grammars; frozen no-slots). Every capability’s create_contract(..., suppress_common_words: bool = False) forwards it. Default False preserves existing canonicalize() / scan() results; True removes word-bounded short-code recognitions whose lowercased span is in the curated table — never canonicalizing, only suppressing recognition (provenance-neutral by construction).

Table: paxman/core/grammar/data/common_words.py:COMMON_WORDS frozenset[str] curated via Google 1000 (https://github.com/first20hours/google-10000-english, google-10000-english.txt first 1000 lines) ∩ (ISO 3166 α2/α3 + ISO 4217 + ISO 639-1/2/3) lowercased, reviewable, frozen with assert len(COMMON_WORDS)==67 and assert "USD" not in COMMON_WORDS. USD is deliberately not suppressed (not in Google 1000); currency scan() keeps USD while to/in etc. are removed for country/currency/language code shapes.

Matchers: short-code matchers marked suppressible=True (declaration, not per-grammar code): Country alpha2_recognition / alpha3_recognition / numeric_recognition, Currency code_recognition, Language language_code_recognition. Boundary is already word-bounded (BoundarySpec.WORD / WORD_SIGN — required), so suppression only fires on word-bounded hits.

Engine: paxman/core/grammar/engine_loop.py insertion between view.original_span and emit: when contract.suppress_common_words and matcher.suppressible and text[o_s:o_e].lower() in COMMON_WORDS → continue (skip emit).

Scan vs canonicalize:

• scan("Ship to the United States of America, total 45.50 USD, weight 3.5 kg", [Country.create_contract(suppress_common_words=True)]) keeps only the name mention United States of America for the short-code shapes (plus numeric/already-word-bounded non-common-word hits); with the flag off the full current snapshot is preserved. Currency scan keeps USD in both modes.
• canonicalize("to", Country.create_contract(suppress_common_words=False)) → SUCCESS "TO" (Tonga correct for bare code); with the flag on → MISSING (suppressed recognition, never validated).

CLI: paxman scan keeps default contracts (flag off) but now accepts --suppress-common-words — thin create_contract(suppress_common_words=True) construction only (see paxman scan --help). API remains the seam for canonicalize().

ADR: Rev.4 §16 “deferred, non-binding” is superseded — the table ships in 0.2.0 off by default. recognition_revision bumps for the new matcher marker (one-time, pre-release).

Migrate: no change required. Opt in only for scan() on prose where Tonga noise matters; keep bare-code canonicalize() contracts flag-off.

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Unreleased — toward 0.6.0 (minor)

Scope: additive capabilities plus recognition/validation narrowings. No contract shape changes; existing contracts still validate. Result changes below are data-driven or spec-alignment fixes — re-run golden samples.

0.4.1 — docs-only patch, no migration

0.4.0 → 0.4.1 changed user documentation only (no contract, grammar, rule, or data change). No migration required.

Unreleased — New capability: UUID (additive)

UUID (lowercase hyphenated canonical, compact/braced/urn offered re-encodings, IETF RFC 9562, structure-only validation) is registered by register_all_shipped() (now 21 shipped). No migration required — existing contracts are byte-identical. See the UUID guide and the Citations IETF row.

Unreleased — New capability: DOI (additive)

DOI (bare lowercase 10.registrant/suffix canonical, url offered re-encoding, ISO 26324:2025, structure-only validation, no checksum, no registry) is registered by register_all_shipped() (now 22 shipped). No migration required — existing contracts are byte-identical. See the DOI guide and the Citations ISO row.

Unreleased — New capability: ISIN (additive)

ISIN (compact uppercase CC+NSIN+C canonical, grouped CC NNNNNN NNN C offered re-encoding, ISO 6166:2021 structure + modulus 10 Double-Add-Double check digit plus ANNA ISIN Guidelines V25 prefix allowlist) is registered by register_all_shipped() (now 23 shipped). No migration required — existing contracts are byte-identical. See the ISIN guide and the Citations ISO/ANNA rows.

Unreleased — New capability: MinorPlanet (additive)

MinorPlanet (unpacked canonical 1995 XA / (433) / 2040 P-L, packed offered re-encoding, MPC DesDoc + PackedDes + HowNamed structure-only, no registry) is registered by register_all_shipped() (now 30 shipped). No migration required — existing contracts are byte-identical. See the MinorPlanet guide and the Citations Minor Planet Center rows.

Unreleased — New capability: UNSPSC (additive)

UNSPSC (8-digit wire-stem canonical, labeled and native offered re-encodings, UNGM structure + UNDP codeset snapshot + UNECE BFI suffix) is registered by register_all_shipped() (now 29 shipped). No migration required — existing contracts are byte-identical. See the UNSPSC guide and the Citations UNDP/UNECE rows.

Unreleased — New capability: ISNI (additive)

ISNI (spaced display XXXX XXXX XXXX XXXC canonical, compact 16-char and urn urn:isni:<compact> offered re-encodings, ISO 27729:2024 structure + MOD 11-2 check digit) is registered by register_all_shipped() (now 28 shipped). No migration required — existing contracts are byte-identical. See the ISNI guide and the Citations ISO row.

Unreleased — New capability: LEI (additive)

LEI (compact uppercase LOU4+entity14+check2 canonical, urn urn:lei:<compact> offered re-encoding, ISO 17442-1:2020 structure + whole-string MOD 97-10 check digits plus GLEIF LOU prefix-list membership) is registered by register_all_shipped() (now 24 shipped). No migration required — existing contracts are byte-identical. See the LEI guide and the Citations ISO/GLEIF rows.

Unreleased — New capability: GTIN (additive)

GTIN (14-digit zero-padded canonical, native spelled-length offered encoding, GS1 General Specifications 26.0 structure + Mod-10 check digit plus GS1 Prefix allocation membership, optional Verified-by-GS1 snapshot lookup enabled by include_verified=True (default False, disabled)) is registered by register_all_shipped() (now 25 shipped). No migration required — existing contracts are byte-identical. See the GTIN guide and the Citations GS1 rows.

Unreleased — New capability: CreditCard (additive)

CreditCard (compact contiguous 12–19-digit canonical, pan default / grouped offered groups-of-four encoding, ISO/IEC 7812-1:2017 structure + Luhn MOD-10 plus brand IIN/length membership enabled by include_brand_validation=True (default False, disabled)) is registered by register_all_shipped() (now 26 shipped). No migration required — existing contracts are byte-identical. See the CreditCard guide and the Citations ISO and Brand networks rows.

Unreleased — New capability: Domain (additive)

Domain (lowercase ASCII A-label canonical, unicode offered U-label encoding, RFC 1034/1035 structure + UTS #46 statuses with STD3 rules + RFC 5893 Bidi plus IANA Root Zone Database membership) is registered by register_all_shipped() (now 27 shipped). No migration required — existing contracts are byte-identical. See the Domain guide and the Citations IETF, IANA, and Unicode Consortium rows.

Unreleased — BREAKING: Element → ChemicalElement rename

The element capability is renamed to chemical_element to reserve the bare Element name for future non-chemical element domains (e.g. HtmlElement). Migrate: from paxman.capabilities import ChemicalElement, ChemicalElement.create_contract(), registry chemical_element, CLI paxman chemical_element / paxman scan -c chemical_element, grammar chemical_element_recognition. Input syntax is unchanged (Fe, iron, element 26 → Fe); rule names are unchanged (Section IR-3.1-names-and-symbols, Section PTOE-element-registry). See the ChemicalElement guide.

0.5.0 — New capabilities: Timezone + UtcOffset (additive)

Timezone (IANA key canonical, iana default, no offered formats, include_systemv=False gates EST5EDT and kin) and UtcOffset (extended +HH:MM canonical, basic +HHMM offered re-encoding) are registered by register_all_shipped() (now 20 shipped). No migration required — existing contracts are byte-identical. See per-capability guides under Capabilities and the Citations IANA/ISO rows.

0.5.0 — Language compositional descriptions + bare-code narrowing (changed)

• Bare 5–8 letter runs (hello, Xenon, script) → MISSING (were INVALID; no hyphenless 5–8 primary exists in the shipped set).
• Parenthesized descriptions (Chinese (Traditional, Singapore) → SUCCESS zh-Hant-SG) resolve directly under the default contract.
• Compositional in-forms (Singapore Chinese in traditional script) → AMBIGUOUS under the default contract (full-phrase reading vs bare in→id), SUCCESS with suppress_common_words=True; Wave-2 script/region displays extended (7 scripts, 8 single-token regions; multi-token regions and thai deferred).
• nb renders Norwegian Bokmål (was Norwegian Bokmal) via the display-name companion.

Migrate: if you asserted bare 5–8 INVALID, update goldens to MISSING; if you depend on compositional inputs, pass the suppression contract or handle AMBIGUOUS.

0.5.0 — Money $ constrained to own candidates (changed)

dollar_sign_currency now resolves only to one of the symbol’s own CLDR candidates ($500 + USD → SUCCESS; $500 + MYR → INVALID, was SUCCESS; mirrors Currency default_currency). Single-candidate symbols (€500) and qualified symbols (US$, CA$) are unaffected.

Money.create_contract(dollar_sign_currency="USD")  # $ → USD only when USD is a $ candidate

Migrate: if you passed a non-candidate code with a shared symbol, expect INVALID now; pass one of the symbol’s own candidates instead.

0.5.0 — BIC end-of-text English-phrase filter (changed)

call me at at end-of-text, before punctuation/parentheses, or before a non-alphanumeric tail no longer recognizes as a BIC (was a false SUCCESS candidate). CALL ME AT (all-caps) still recognizes via the isupper() gate.

Migrate: if you asserted the lowercase phrase claimed a BIC, update goldens to MISSING.

0.5.0 — Candidate qualification, ADR-0012 (changed)

A PARSER candidate survives only with LOOKUP_TABLE corroboration on the same recognition (plus per-grammar keep_duplicate_spans scoping):

Input	Contract	Before	After
Serbo-Croatian	Language defaults	AMBIGUOUS (serbo-croatian ghost + sh)	SUCCESS "sh" (ghost disqualified)
xx-yyyyy	Language defaults	SUCCESS (syntax alone)	INVALID (no authority entry)
en-x-private	Language defaults	SUCCESS (syntax alone)	INVALID (two-locus model; SUCCESS with include_private=True)

Contracts filtering the lookup authority out (pinned_rules / excluded_rules / year / requires_features gating) preserve parser candidates per the vacuity clause — no change there. Kernel Slice A/G/H fixes (boundary bracket-escapes, quantifier-aware widths, combinator backtracking, single ordering space) move no shipped vectors — no migration.

What can appear in a minor release

You do not need to change code for these — they are additive and backward compatible:

• New capabilities (the set of importable names under paxman.capabilities grows — never treat a current count as final).
• New contract flags of the form include_*, allow_*, or default_* (always optional, defaults preserve shipped behavior).
• New offered output_format alternatives (the default rendering stays the same; pin output_format if you rely on a specific rendering).
• Expanded authority tables (e.g. new CLDR entries, additional URL IDNA mappings) where the spec itself grew.

Keep your registration future-proof by preferring the explicit form when you care about the surface:

# Future-proof — only the capabilities you name
paxman.register_capability(Email())
paxman.register_capability(Date())

# Convenience — everything shipped in this build
paxman.register_all_shipped()  # convenient, but the set it registers grows over time

Either approach is supported; pick explicit when you want the upgrade to be a conscious decision, and bootstrap when you want the new capabilities automatically.

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What signals a careful upgrade

These are major-bump signals — check the release notes and review the checklist below:

• A DEFAULT_OUTPUT_FORMAT or OFFERED_OUTPUT_FORMATS change — the string behind canonicalized_value for the same input may differ even though status stays SUCCESS.
• A rule’s provenance year or spec version changes — treat as an audit signal: contract.year boundaries move and include_historical vs active coverage may shift. Alone it is not a MAJOR trigger (see above).
• A capability renamed, merged, or removed.

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Upgrade checklist (copy-paste)

When moving to a new MINOR, glance; when moving to a new MAJOR, work through it:

1. Read the release notes — skim new capabilities, new contract flags, and any new output_format values. Decide whether a new capability belongs in your registration.
2. Review contracts — new optional flags default to shipped-preserving values. Verify that rule names in pinned_rules and excluded_rules still exist (a stale name raises ContractError), and separately confirm that year (filters publication_year <= year) still expresses the temporal window you intend — year is not a rule name.
3. Pin output if it matters — if your downstream expects a specific rendering (e.g. Phone rfc3966), construct the contract with output_format="rfc3966" rather than relying on the current default.
4. Re-run your golden samples — keep a small file of (text, contract) → canonicalized_value samples for the capabilities you use, assert them in CI, and compare after the upgrade. Determinism means a change is intentional, not noise.
5. Log or store version_stamp — for audit trails, persist result.version_stamp.paxman_version alongside canonicalized_value so you can explain which build produced which answer.
6. Segmentation review — if you added a new capability or flag, confirm the caller-owned split-then-canonicalize loop (see Segmentation) still routes each piece to the right capability/contract.

Re-entry: a SUCCESS canonical value V is safe to feed back as canonicalize(V, C) → SUCCESS V for any output_format under the same default contract (ADR-0010, #123). Custom pinned_rules/excluded_rules/year, and embedded or otherwise non-exempt suppressed matches, remain conditional.

Minimal golden-sample harness:

import paxman
from paxman.capabilities import Email, Country
from paxman.core.domain import Resolution

paxman.register_all_shipped()

checks = [
    ("user@Example.COM", Email.create_contract(), "user@example.com"),
    ("United States", Country.create_contract(), "US"),
]

for text, contract, expected in checks:
    r = paxman.canonicalize(text, contract)
    assert r.status == Resolution.SUCCESS and r.canonicalized_value == expected, (
        text,
        r,
    )

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Temporal filtering and data drift

Spec tables (CLDR, ISBN Range Message, URL IDNA) are regenerated from snapshots and live inside the library. When a spec evolves (new country names, new currency symbols, new IDNA mappings), the release notes will note it. Use contract.year to pin to specs published up to a given year when reproducibility against a point-in-time authority matters; combine it with a pinned paxman version in your environment for full reproducibility.

See Contracts for year filtering, Provenance for publication_year on each citation, and Execution Result for version_stamp.

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See also

• API Reference — registration, contracts, and statuses
• Concepts — Pipeline — why statuses are stable (recognition → validation → resolution)
• Extending — keeping community grammars/rules compatible across upgrades
• Segmentation — caller-owned splitting for multi-entity text