Compatibility Notes

Canonical number boundary

Number mode is answer semantics only: int or float. Numeric visual presentation uses display-style: input, slider, or dial.

Rating scale boundary

Rating mode="scale" is the canonical default and may be omitted. Legacy matrix may parse where compatibility is intentionally retained, but new GUI output should use scale terminology or omit the default mode.

Display-style boundary

Question-level display-style="carousel" or display-style="accordion" is type-aware. It is not the same as number display style.

Media question boundary

video and glb are uploaded-asset media gate question types. They can block progress when required, but they do not create normal response or export columns. Use a separate question or run-code answer when acknowledgement must be recorded.

Overlay source compatibility

The current selected-language Overlay source is a rootless list of <entry key="...">...</entry> tags. Legacy full <overlay><language>...</language></overlay> documents may be read and split for compatibility, but new selected-language editing should preserve the rootless fragment shape.

Public style fallback

Public Survey Link falls back to Classic Clean only when no explicit safe saved style selection is available. The fallback is runtime presentation only and does not rewrite the stored style selection.