Schema Evolution

Xlang compatible mode carries schema metadata so readers can tolerate supported field additions, removals, and reordering. Same-schema mode reduces metadata only when every reader and writer uses the same schema.

Choose compatible or same-schema mode

Keep compatible mode for independently deployed peers. Use same-schema mode only after verifying that every runtime uses the same field identities, nullability, reference metadata, and types.

Runtime APIs and examples live in each runtime's schema-evolution.md page. Normative schema metadata and compatibility behavior are defined by the xlang serialization specification.