2026.9.9

Changes for existing forms

Three behaviors changed. Check forms written against earlier versions.

• data-fs-relevant on one member of a choice group now governs that member alone. To hide or disable a whole group, put the attribute on its fieldset.
• required on any member of a checkbox set now requires the set, as it does on a radio group.
• A choice group with some disabled or irrelevant members now submits its enabled members. The submission protocol's omission rule is per control.

New

• Member relevance: data-fs-relevant on a choice-group member or on an option, with hidden and disabled modes. See Member Relevance in the vocabulary spec.
• Conditional requiredness: data-fs-required="expression" makes a field required only while the expression is true. See Conditional Requiredness in the vocabulary spec.
• Lone toggle rows: a row whose label wraps its own checkbox gets the styled toggle look and aligns with the rows around it.

Server implementations need updating for the first two items.

Full Changelog: 2026.8.26...2026.9.9