---
id: DFMOD-C9-POS-004
title: "Question ID continuity and empty-value handling stay stable across versions"
product: web
module: digital-form
type: functional
priority: P1
risk: high
status: draft
automationStatus: planned
sourceRefs:
  tsd: PK141
  tsdSection: C9
  tsdScenario: C9.4
  prd: PK141
  jira: null
automationRef: null
lifecycleStatus: active
lifecycleReason: "AI-generated draft from PK141 TSD C9.4; pending QA review."
lastReviewedAt: null
reviewedBy: null
supersededBy: null
duplicateOf: null
blockedBy: null
preconditionRefs:
  - PRE-DF-submitted-report-exists
tags:
  - web
  - digital-form
  - export-report
  - question-id
  - client-portal
  - pk141
  - staging
---
## Objective
Verify export keeps a consistent Question ID mapping and uses empty values (never overwrite) for incompatible rows.

## Preconditions
- See [[PRE-DF-submitted-report-exists]]
- And one question's structure changed across versions

## Steps
1. Export combining old and new rows

## Expected Result
- Then a consistent Question ID mapping is preserved per the evolution rule
- And rows incompatible with the latest structure produce empty values, not overwriting old data
- And all versions remain analyzable in one export without losing historical meaning
- And single→subfield→single and compound→non-compound do not corrupt old columns

## Source Traceability
- TSD: PK141
- Section: C9 - Version Integrity
- Scenario: C9.4 - Question ID consistency and empty-value handling
- Acceptance Criteria: PRD C.36 Scenario 6-8

## Evidence Required
- Export with stable Question IDs + empty (not overwritten) incompatible cells.

## Notes / Gaps
- No gap.