mathlib-fp 1.9.7 release notes

Version 1.9.7 is the migration and compatibility rehearsal. It proves source edits and package boundaries before 2.0 changes any documentation default. It does not remove or deprecate a maintained 1.x declaration and does not add a runtime dependency.

Executable migration evidence

• Independent supported-1.x and candidate-2.0 projects compile and run across all 13 documented domains.
• Each project asserts construction, ordinary success, a diagnostic failure contract, ownership/copy behavior, indexing, precision, defaults, and result interpretation. Expected compiler warnings are recorded and currently empty.
• tools/check_migration_rehearsal.py validates the machine-readable contract, compiles/runs both consumers plus the package-boundary consumer, verifies the Lazarus package unit/dependency boundary, and writes host-specific evidence.
• The same checker is part of ordinary CI and clean-archive release qualification; no network or third-party numerical package is required.

Compatibility decision

TPressureKit, EPressureError, TVelocityKit, and EVelocityError remain supported in EngineeringLib.Pressure and EngineeringLib.Velocity. Executable evidence confirms exact facade/exception identity and equal defaults, ownership, failure behavior, and numerical results. The main Lazarus package already includes both focused and canonical units and still depends only on FCL.

New code spanning pressure, velocity, and flow may prefer TFluidDynamicsKit/EFluidDynamicsError. That documentation preference is not a deprecation: 1.9.7 emits no warning, performs no package move, and starts no removal runway.

External-library migration guidance

The migration rehearsal guide publishes conceptual mappings from common NumLib and LMath/DMath tasks to mathlib-fp. Mappings call out zero-based storage, shapes, ownership and mutation, precision, defaults, callbacks, convergence/status interpretation, package and licensing boundaries, and unsupported cases. They are source-migration directions, not ABI, symbol-name, random-sequence, or drop-in compatibility.

Upgrade notes

• Existing 1.9 code requires no edit.
• The public 1.9 interface remains frozen; the API snapshot has no declaration addition, removal, or signature change.
• To adopt candidate conventions early, compare the two consumer projects and make only the documented import/storage/diagnostic edits.
• Re-run application-specific reference values, residual checks, and edge cases after migrating from another numerical library.

Qualification boundary

Local Windows x86-64 FPC 3.2.2 consumer and Lazarus 4.8 package evidence is recorded in QUALIFICATION_1.9.7.md. Exact Linux and Windows clean-archive candidate jobs remain mandatory before tagging; no local result is generalized to a target that did not run.