With mainstream maintenance for SAP ECC 6.0 ending in 2027, many companies are now choosing how to move to SAP S/4HANA. There are three broad routes, and the right one depends less on technology than on how much you want your processes to change.
| Approach | What it means | Best when |
|---|---|---|
| Greenfield | A new implementation with redesigned processes; selected data is migrated. | Processes are outdated or heavily customised and you want a clean start. |
| Brownfield | A system conversion that keeps configuration, custom code and history. | Current processes work well and minimising disruption is the priority. |
| Selective transition | A mix: some processes redesigned, selected history and configuration carried over. | You have several company codes or want to change some areas, not all. |
Five questions that decide the route
- How much of your custom ABAP code is still used? Usage analysis often shows a large share can be retired.
- How much historical data do users genuinely need in the live system?
- Do you plan to standardise processes across business units or acquisitions?
- What business events — year-end, peak season, audits — limit your cut-over windows?
- Do you have the internal capacity to run change management alongside daily work?
Whichever route you choose
Start with a readiness check, clean master data early, keep extensions outside the core where possible, and plan testing and user training as seriously as the technical conversion. Those four habits do more to protect the timeline than the choice of route itself.
Need an assessment of your landscape? Our SAP Services team compares cost, risk and timeline for each route.