{
  "schema": "DAT005_TRANSFER_TEMPLATE_v1",
  "independent": true,
  "case": "A billing system replaces nullable free-text tax_region_text with validated tax_region_code while two application versions overlap.",
  "required": [
    "old/target contract",
    "transition states",
    "data readiness gate",
    "old/new reader-writer matrix",
    "lock/rewrite source check",
    "recovery decision",
    "removal gate",
    "residual limitation"
  ],
  "answer": ""
}