Versioning and Amendment Control

19.1 Version numbering

ARCS uses a major.minor version scheme. A major version increment (e.g., v1 to v2) denotes structural changes to control families, conformance levels, or the surface model that may require reassessment. A minor version increment (e.g., v1.3 to v1.4) denotes additions, clarifications, or expanded coverage that do not invalidate prior conformance claims but may introduce new requirements for higher conformance levels. Errata corrections that do not change normative requirements are denoted by a patch identifier and do not constitute a new version for conformance purposes.

19.2 Transition period

Conformance claims issued under a prior version remain valid for 12 months after publication of a new major version, provided the assessor documents a gap analysis identifying new requirements introduced by the current version. Claims older than 24 months without renewal or gap analysis are considered stale and SHALL not be cited as current conformance evidence.

Minor version increments do not trigger the transition period. An implementation conforming to v1.3 remains conforming through v1.x unless the implementation's declared conformance level requires controls introduced in a later minor version.

19.3 Amendment authority

Amendments to ARCS are published by Vega Commons Project, Inc. The amendment process includes public notice of proposed changes, a comment period for adopters and assessors, and a reconciliation review before publication. Emergency errata affecting the correctness of normative text may be published without a comment period, provided they are documented in the version history with the rationale for expedited publication.

19.4 Backward compatibility

New versions of ARCS SHALL not retroactively invalidate conformance that satisfied all requirements of the prior version at the time of assessment. Where a new version introduces requirements that would change the conformance status of an existing implementation, the transition period in Section 19.2 applies.

19.5 Conformance statement version reference

All conformance statements, attestation artifacts, and assessment reports SHALL reference a specific ARCS version number. Conformance claims that do not reference a version are non-conforming. Where an implementation undergoes reassessment, the new assessment SHALL reference the current version.