The Migration Imperative

With SAP ending mainstream maintenance for ECC by 2027, enterprises running legacy SAP systems face a clear deadline. But migration to S/4HANA isn't just about avoiding end-of-life — it's an opportunity to reimagine business processes from the ground up.

Deadline alert: SAP mainstream maintenance for ECC ends in 2027. Extended maintenance runs through 2030 at premium cost. The window to migrate on your own terms — not under pressure — is now.

Practice 1: Choose Your Migration Path Deliberately

Three paths exist, each with distinct trade-offs:

  • Greenfield — New implementation on a clean system. Best for companies with heavily outdated processes willing to redesign from scratch.
  • Brownfield — System conversion preserving customizations and historical data. Fastest path for stable, mature SAP landscapes.
  • Selective Data Transition — Hybrid approach: migrate selective business units or data sets. Highest flexibility, highest complexity.

Our recommendation: unless your current system is heavily customized with strong business justification, brownfield conversion delivers 30% faster timelines and lower risk.

Practice 2: Data Quality Before Everything

80% of migration delays trace back to data quality issues discovered too late. Run data profiling and cleansing 3–6 months before migration begins — not during.

80%
of S/4HANA migration delays are caused by data quality issues found too late in the project

Practice 3: Custom Code Remediation Early

Use SAP's Custom Code Migration tool to identify incompatible ABAP objects. Remediate in parallel with other workstreams — don't treat it as a sequential gate that blocks everything else.

Custom code remediation is the hidden iceberg of SAP migrations. The surface shows a few hundred objects. Below the waterline is where the project timelines live or die.

Practice 4: Test with Real Transaction Volumes

Performance testing with production-like data volumes catches issues that unit and integration testing completely miss. We've seen migrations pass all functional tests, then fail catastrophically under real Monday-morning load.

Never sign off on go-live readiness based on functional tests alone. Volume performance testing with a full production data copy is non-negotiable for any system processing more than 10,000 daily transactions.

Practice 5: Change Management Is Not Optional

The Fiori UX in S/4HANA fundamentally changes how every user interacts with SAP daily. Budget 15–20% of total project effort for training, communication campaigns, and structured user acceptance testing.

Migration Path Typical Timeline Data Retention Recommended When
Greenfield 12–18 months None (fresh start) Process overhaul needed
Brownfield 8–12 months Full history Stable, mature systems
Selective Transition 10–16 months Selective Complex multi-entity orgs

The projects that succeed treat S/4HANA migration as a business transformation program with an IT component — not an IT project with some business change on the side.