Versioning and Stability

Formualizer is moving quickly. Treat upgrades as engineering changes, not just dependency bumps.

Safe upgrade workflow

1. Pin versions in Cargo/Python/npm lockfiles.
2. Read release notes and check changed APIs in Rust + bindings.
3. Run workbook regression tests on your own critical models.
4. Validate cross-binding parity if you ship more than one runtime.

Commands worth running during upgrades

# Rust core/workbook
cargo test -p formualizer-eval
cargo test -p formualizer-workbook

# Python bindings
./scripts/dev-test.sh

# WASM bindings
cd bindings/wasm && npm test

Compatibility posture to assume

• Behavior is strongest where there is explicit engine/binding test coverage.
• New feature surfaces (for example plugin runtime seams) may still evolve.
• Prefer additive integration patterns where possible (new functions/pages) over deep monkeypatching.
• FormulaPlane span evaluation was removed in 0.10.0. Its switches (with_span_evaluation, FormulaPlaneMode and the Python/WASM toggles) are still accepted but ignored, so existing code keeps compiling with unchanged values. Copied-formula families now run on the default engine.

Next

• First Workbook in 5 Minutes
• Deterministic Testing