elfware
12-month parallel run, 8 flawless cutovers — zero rollbacks

12-month parallel run, 8 flawless cutovers — zero rollbacks

UK E-Commerce Retailer — ERP Integration @ Speed

Phase transition, zero rollbacks, 12 months of synchronised trading

Client: [Anonymised]
Sector: Retail / E-Commerce
Region: UK
ERP: Oracle Retail MOM & RDF + Merrett Retail ERP
Scope: Merchandise, Orders, Fulfilment, Pricing, Forecasting, Replenishment

At a glance

  • Critical rollbacks: 0
  • Reconciliation coverage: 100% (in-scope)
  • Lead-time reduction: 8 parallel cutovers delivered on schedule
  • Validations per cycle: Thousands of printed processes

Challenge

The £4 billion TGR – Truly Global Retail programme needed Oracle Retail to run in parallel with Merrett, their legacy Retail ERP platform. To de-risk high-traffic website and distribution operations, the migration was split into eight cutovers. Manual dual data entry and reconciliation between platforms at this scale was too slow and error-prone.

Approach (Assess → Stabilise → Prototype → Migrate → Verify)

elfware printed a temporary integration layer to keep legacy and target platforms synchronised during phased transition. Using Enterprise Low Code and Data Patterns, we automated delta detection, quarantine and release, visualisation, and base/API-level ingestion — enabling each phase to complete independently without service disruption.

What we did

  • Reused existing data migration source mappings
  • Implemented delta processes to identify and process data changes between systems.
  • Introduced quarantine rules for integrity-fail records with automatic release once validated.
  • Delivered visual dashboards for quarantine/release status and progress tracking.
  • Deployed API-based delta ingestion into Oracle Retail via base and custom connectors.
  • Supported eight distinct transition states over 12 months with zero data fixes.

Outcomes

  • Seamless synchronisation across all eight transition phases.
  • No critical rollbacks or rework - no impact on business.
  • Clean decommission of final legacy interfaces after Cutover 8.
  • Delivery speed and reliability led to elfware expanding into additional programme scope.

Timeline

  • Weeks 1–4: Prototype delta integrations
  • Weeks 5-8: Stabilise, validate processes and UAT
  • Months 3 +: Phased cutovers and rehearsals (1–8)
  • Month 14: Final legacy switch-off and hypercare

Security & Governance

Executed within approved programme environments (20 +). Daily data flows of 100–200 GB. elfware Enterprise Low Code platform passed customer security and audit reviews.

"No other retailer has been able to deliver a parallel run like us — and it would not have been possible without the elves!" — Retail Programme Manager

"No other Oracle Retail customer we know has been able to deliver a parallel run like TGR — and we could not have done it without the elves." — Programme Director, UK E-Commerce Retailer (TGR - Truly Global Retail programme)

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12-month parallel run, 8 flawless cutovers — zero rollbacks - elfware