Dual-Landscape S/4HANA Migration for Global Retailer
Global Specialty Retailer
Business Context
The organization and its strategic environment
A $4.5B specialty retailer with 1,800 stores across 12 countries needed to migrate to S/4HANA but could not risk disrupting holiday season operations (60% of annual revenue). The solution required running dual landscapes — old ECC for stores and new S/4HANA for corporate — before a phased store migration.
Technology Landscape
Systems and infrastructure before DGT
SAP ECC 6.0 Retail, SAP CAR (Customer Activity Repository), SAP POS, 1,800 store systems with real-time integration, SAP BW for merchandise analytics, and custom allocation/replenishment engines.
The Challenge
What the client was facing
A big-bang migration was unacceptable — any disruption during peak season would cost $50M+ in lost revenue. But running parallel systems indefinitely was cost-prohibitive. DGT needed to design a dual-landscape coexistence strategy that allowed phased migration by region while maintaining unified reporting.
The DGT Solution
How DGT addressed the challenge
DGT architected a dual-landscape coexistence model: S/4HANA for corporate finance, procurement, and HR went live first. Store operations remained on ECC with real-time synchronization via API Hub. Stores were then migrated region-by-region during off-peak periods over 9 months. Insights360 provided unified reporting across both landscapes throughout.
DGT Accelerators Used
Delivery Approach
How DGT executed the engagement
'Coexistence-First' methodology: build the bridge before crossing. We deployed API Hub as the synchronization layer between ECC and S/4HANA, ensuring both systems had consistent master data and transactional integrity. Regional store migrations followed a repeatable playbook — each region took 3 weeks.
Governance Model
How the engagement was managed
Dual-track PMO: one track for corporate S/4HANA, one for store migration waves. Unified risk register with revenue-impact scoring. Weekly coexistence health checks. Regional go/no-go decisions based on transaction volume thresholds.
Timeline & Phases
The execution roadmap
Coexistence Architecture
8 weeksAPI Hub design, data sync rules, unified reporting model
Corporate Go-Live
12 weeksFinance, procurement, HR on S/4HANA with ECC coexistence
Store Migration Wave 1
3 weeks200 stores in lowest-volume region (pilot)
Store Migration Waves 2-6
15 weeks1,600 remaining stores in 5 regional waves
ECC Decommission
4 weeksFinal data archival, ECC shutdown, cost savings realization
Risks Addressed
Key risks DGT mitigated during the engagement
Why DGT Won
What set DGT apart in this engagement
Outcome Metrics
Measurable before-and-after results
| Metric | Before | After DGT |
|---|---|---|
| Migration Duration | N/A | 9 months (all 1,800 stores) |
| Peak Season Disruption | N/A | Zero |
| Annual SAP Costs | $18M (dual) | $9M (single S/4HANA) |
| Reporting Latency | T+1 day | Real-time |
The Impact
Headline results delivered
"DGT's dual-landscape approach was brilliant — we never had to choose between risk and speed. Corporate went live immediately, stores followed safely, and we never lost a single transaction."
Jennifer Walsh
Global CTO, Global Specialty Retailer