Version
Compatibility
The conformance rules for determining whether implementations, normative encodings, durable representations, and Specifications remain compatible as the governing Survey standard evolves.
Version Compatibility establishes how a conforming implementation proves that it applies the correct governing Survey specification, profile, and serialization identity while preserving established canonical spatial meaning across compatible evolution.
The current candidate core now has concrete compatibility obligations: CRPC meaning, canonical frame semantics, Point / Segment / SCPE geometry, exact predicates, normalization, ECEM precision semantics, and FSF-CJSON-1.0 behavior must remain stable across any evolution declared compatible.
Compatible evolution may extend capability or representation. It shall not renumber, relocate, reinterpret, reuse, or otherwise mutate established canonical place. Open mathematical gates and future profiles remain outside compatibility claims until formally defined.
Day #126 lineage reconciliation distinguishes mathematical identity, representation identity, format identity, and Specification identity. Compatible evolution may alter the latter three only where lossless, deterministic correspondence preserves the same normalized mathematical object and established canonical place.
Conformance Principle Version the standard. Do not version the place.
Compatibility Can Now Be Tested Against a Concrete Candidate Core
The solved candidate profile provides stable semantics that future compatible versions must preserve.
Conformance may therefore test continuity of CRPC values, canonical Point meaning, geometry normalization, exact predicate behavior, ECEM precision semantics, and FSF-CJSON-1.0 results across any transition that claims compatibility.
The Applicable Standard Must Be Explicit
A conforming implementation shall identify the governing Foundational Survey Fabric Specification version or compatibility identity, the conformance profile being claimed, and the applicable normative encoding identity where defined.
Version or profile ambiguity shall not be permitted to alter authoritative interpretation.
Final top-level FSF Specification identifier syntax remains open and shall not be invented by Conformance.
New Versions May Extend Without Moving Place
A later compatible Specification version may clarify rules, improve Conformance material, add optional capabilities, extend finite representational capacity, or introduce additional governed durable representations.
Such evolution shall preserve every previously valid canonical meaning within the compatibility scope.
Representations may evolve. Canonical place may not drift.
Previously Valid Exact Coordinate Values Must Retain Their Meaning
A compatible version shall not change the exact mathematical value denoted by an existing valid CRPC representation.
Compatible extension may permit additional exact values, but previously valid values shall remain valid with unchanged meaning.
Precision Extension Must Not Migrate Place
Compatible evolution shall preserve the Exact Coordinate Extension Model.
A canonical Point that denoted one exact Survey position under an earlier compatible profile shall continue to denote that same position under a later compatible profile.
Increased representational capability shall not transform an old Point into a coarse cell, parent reference, uncertainty region, or different position.
Established Point · Segment · SCPE Meaning Must Remain Stable
Compatible evolution shall preserve the canonical meaning of previously valid Point, Segment, and SCPE objects.
A later compatible profile may add new geometry types only through explicit Specification governance and shall not reinterpret previously valid primitive geometry.
Compatible Versions Preserve Existing Exact Results
Where an exact predicate, validity rule, or normalization rule remains within the declared compatibility scope, the same valid inputs shall continue to produce the same authoritative result.
Compatible evolution shall not silently reverse orientation results, change containment truth, alter geometric equivalence, or cause previously canonical normalized geometry to normalize differently without an explicit incompatible-change classification.
FSF-CJSON-1.0 Meaning and Canonical Bytes Must Remain Governed
FSF-CJSON-1.0 is the current candidate canonical machine representation for the solved profile.
Any later compatible evolution that continues to claim FSF-CJSON-1.0 compatibility shall preserve the format’s governed meaning and canonical byte rules for previously valid objects.
A future encoding may be introduced only through explicit Specification governance defining its relationship to existing canonical meaning and compatibility obligations.
Compatible Versions Preserve Canonical Results
Where an operation and its canonical semantics remain unchanged across compatible Specification versions or profiles, identical canonical inputs shall continue to produce the same authoritative canonical meaning.
Where the applicable serialization or normalized form is also unchanged, that canonical representation shall remain identical.
A version change shall not silently alter canonical output under an unchanged rule set.
Previously Valid Canonical Truth Must Remain Interpretable
A compatible later implementation shall remain able to interpret previously valid canonical references and expressions whose meaning was established under earlier compatible versions, subject to the declared compatibility scope.
Historical canonical truth shall not become ambiguous merely because the standard gains new capability.
Unknown Capability Must Not Be Invented
An implementation encountering a future extension, geometry type, operation, or optional capability it does not understand shall not fabricate canonical interpretation for that unsupported feature.
Forward-compatibility behavior shall preserve known canonical meaning while clearly identifying unsupported capability.
Do Not Guess Across Unknown Versions
An implementation shall not silently interpret an unknown, unsupported, or incompatible Specification profile or normative-encoding version according to another version’s rules.
Unsupported or indeterminate forms shall be rejected or explicitly classified according to the governing Conformance rules.
Unresolved Mathematics Cannot Be Claimed Compatible Yet
Compatibility applies only to behavior whose canonical semantics are actually defined.
Current open examples include unresolved Survey Domain numerical half-span H, general Boolean/composite output closure, arbitrary exact rotation, unresolved general distance and path-length scalar forms, future geometry not yet selected, and other still-open Specification capabilities.
A future version that resolves an open gate does not retroactively imply that earlier implementations possessed canonical behavior for it.
Spatial Mutation Is Not Ordinary Compatibility
A proposed change that would alter established canonical spatial meaning shall not be treated as ordinary compatible Specification evolution.
Such a change belongs to a fundamentally different architectural or constitutional decision class and shall not be disguised as routine version evolution.
If BitPangea ever authorizes an intentionally incompatible successor, that transition would require separate institutional Specification succession / migration governance. Conformance may detect and classify the incompatibility; it does not authorize the transition.
Governance over the standard does not create authority to reinterpret protected immutable spatial truth.
Version Metadata and Representation Do Not Become the Place
Mathematical identity, representation identity, format identity, and Specification identity are distinct. Version identifiers and format labels govern interpretation, proof scope, and compatibility claims.
They do not become part of the canonical spatial identity of the Point, Segment, SCPE, or Survey location represented. Where compatibility is claimed, differing governed versions or representations must correspond losslessly and deterministically to the same normalized mathematical object.
Compatibility Claims Must Name Their Basis
Every formal conformance claim shall identify the Specification version or compatibility identity available at that stage, the conformance profile, and the applicable normative encoding identity.
For current serialization claims, FSF-CJSON-1.0 shall be identified explicitly.
Compatibility shall be demonstrable against a defined standard rather than asserted generically.
Compatibility Must Be Proven Across Change
Conformance testing shall include transition Reference Vectors or equivalent fixtures sufficient to demonstrate that a claimed compatible evolution preserves established spatial meaning, validity, normalization, required predicate results, precision semantics, and canonical serialization behavior.
Transition tests should expose unintended reinterpretation before a compatibility claim is accepted.
Compatibility Relationships Must Be Declared, Not Assumed
As multiple FSF Specification profiles, serialization versions, or future governed encodings emerge, their compatibility relationships shall be expressed explicitly.
The final machine-readable compatibility matrix, declaration syntax, and transition classification system remain open.
Deprecation Must Not Erase Historical Canonical Meaning
A future deprecation policy may discourage use of an older representation or profile, but deprecation shall not by itself alter the historical canonical meaning of previously valid expressions.
Any transition that cannot preserve prior meaning shall be classified explicitly rather than mislabeled as compatible evolution.
Meaning Drift Is a Conformance Failure
If an implementation changes established canonical meaning solely because it applies a different supposedly compatible Specification version or profile, that behavior shall constitute a Conformance failure.
Failure also includes silently applying the wrong version rules, treating unsupported future capability as known canonical meaning, or claiming FSF-CJSON compatibility while changing governed meaning or canonical bytes for an unchanged object.
Compatibility requires continuity of canonical spatial truth, not merely successful parsing of a newer document or format.
Compatibility Invariants Now Concrete
CRPC meaning preservation; ECEM no-migration semantics; stable Point / Segment / SCPE meaning; exact predicate and normalization continuity; FSF-CJSON-1.0 compatibility; backward interpretation of prior canonical truth; explicit unsupported-capability handling; version-scoped claims.
Still Open in Conformance
Final top-level Specification version identifier; formal Specification version-succession rules; incompatible-transition / migration governance if ever required; machine-readable compatibility declarations; complete compatibility matrix; transition classification syntax; future encoding-version policy; deprecation policy; final transition Reference Vector inventory; and compatibility treatment of future Specification extensions.
Version Compatibility Now Has a Stable Candidate Baseline
The original section correctly established that compatible evolution must preserve place. The solved candidate core now provides concrete invariants against which future compatibility can be tested.
Final version identifiers, formal version-succession rules, incompatible-transition / migration governance if ever required, compatibility matrices, transition syntax, and deprecation policy remain open governance and Conformance work. The continuity rule itself is already clear: compatible evolution may extend capability, but it may not rewrite established canonical spatial truth.
Primary Referenced Findings
This Conformance section is derived especially from Requirements Findings #16–#17, #22, #59–#61, #64, and #84–#85.
Architectural Boundary The Specification may evolve through valid authority. Established spatial meaning may not be rewritten by ordinary versioning, implementation preference, or conformance declaration.