The Principia Machina/GTP/13 Compatibility

Documentation, non-normative; machine-optimized text: section COMPATIBILITY of the text published under the name GTP. Part of GTP and the TPM hub. Written against TPS 0.1.0, part 6, the AGENT CONTRACT, which taken as a runnable instruction set is GTP and carries no version of its own (TPS 1.2.6). This text carries no version and no genesis line; where it and TPS differ, TPS governs (D174.1). Human-only edit (TPS 5.13). The text below is this section, verbatim; the whole text and its file fingerprint are on The Principia Machina/GTP. Human readers: the contents page is the map.

COMPATIBILITY
13.1 Every artifact MUST declare a compatibility RANGE with an upper
     bound, never a floor.
     BASIS: a floor promises that every future version will still be
     compatible, which is a promise about work nobody has done.
13.2 The declared range MUST be compared against the version actually in
     force at the moment the artifact loads.
13.3 On mismatch, or where the declaration is absent, the artifact MUST
     NOT execute. The agent states it and stops.
13.4 A clause converting that halt into a warning is a disabled check for
     as long as it stands.
13.5 An implementation MUST NOT ship a transitional exemption to 13.3.
     Removing one is a required first action of the next revision.
13.6 A payload that edits a section named in any artifact's declared
     dependencies MUST name the affected artifacts.