Lesson 1 of 6
Choosing the path
7 min
Moving from SAP ECC to SAP S/4HANA is often described as a technical project. For a process owner, it is a set of business decisions with deadlines. Which decisions you face, and how many, depends first on the transition path the company chooses. This lesson explains the three paths in business terms and what each one does to your workload.
Our running example is Contoso Motor Co., which has run ECC 6.0 EHP 8 since 2009 and is moving to SAP S/4HANA 2025 in SAP S/4HANA Cloud Private Edition under RISE with SAP, with a Q3 go-live. Dan owns record-to-report, Maria is the order-to-cash key user, Priya leads testing and Luis runs cutover.
The three paths
- New implementation (often called greenfield): a new SAP S/4HANA system, designed largely from SAP standard and best-practice content in fit-to-standard workshops. Master data and open items (open orders, open receivables and payables, stock, balances) are migrated; detailed history usually stays in the old system or an archive.
- System conversion (often called brownfield): the existing ECC system is technically converted to SAP S/4HANA in place, keeping configuration, custom code and transaction history. SAP describes it as a guided technical process for a one-to-one conversion.
- Selective data transition: a tool-based, service-led approach that moves selected configuration, master data and transaction data into a new SAP S/4HANA system, for example to keep history for some company codes while redesigning others.
| What the process owner does | New implementation | System conversion | Selective data transition |
|---|---|---|---|
| Process design | Heavy: design every process again from standard | Light to moderate: mostly keep, redesign by exception | Mixed: redesign chosen areas, keep others |
| Simplification items | Mostly absorbed by the new design | Must decide a business response for each relevant item | Depends on what is carried over |
| Data validation | Validate migrated master data and open items | Validate converted balances, open items, stock and history | Validate both migrated and transferred data |
| Comparison testing | Limited: old and new processes differ by design | Central: same process, should give same results | Central for carried-over areas |
| Training load | High: new processes and apps | Moderate: changed apps and simplification impacts | Varies by area |
Typical decision criteria
The path is a company decision, usually led by the CIO and CFO with advice from architects. Process owners should be asked, and should come prepared, because several of the criteria are business ones.
| Criterion | Points toward | Process owner input |
|---|---|---|
| Need to keep full transaction history in the system | System conversion or selective transition | How far back do audits, warranty claims or analysis really go? |
| Processes are broadly fit and the business wants low disruption | System conversion | Which processes work well today, and which are held together by workarounds? |
| Processes or org structure need major redesign | New implementation | Where is the pain: approvals, controls, reporting, manual steps? |
| Heavy custom code with standard equivalents now available | New implementation, or conversion plus cleanup | Which custom reports and programs do users still rely on? |
| Mergers, divestitures or company code consolidation | Selective data transition | Which entities must be kept, split or combined? |
- Must years of transaction history stay in the live system?Yes → conversion or selective transition · No → all paths remain open
- Do the processes broadly fit, with limited appetite for redesign?Yes → system conversion is the natural fit · No → continue
- Is major redesign of processes or organization the goal?Yes → new implementation · No → continue
- Must entities be split, merged or moved selectively?Yes → selective data transition · No → revisit with the architects
Contoso chose a system conversion. The finance director needed ten years of history in the system for audit and warranty analysis, operations were broadly happy with their processes, and the deadline was tight. That choice sets the shape of Dan's and Maria's year: fewer design workshops, but a long list of simplification decisions and a heavy load of data validation and comparison testing.
What would you do?
At the kickoff, Contoso's CIO says: "It's a conversion, so the business just needs to test at the end." Dan is asked to confirm finance's plan. What should he say?
- New implementation redesigns processes and migrates open items; conversion keeps history and processes; selective transition mixes both.
- The path decides whether the process owner's load is mostly design, mostly validation, or both.
- Business criteria such as history needs, process fit and redesign appetite should shape the path decision.
- A conversion still changes things users see; plan decisions and validation from the start.
Check your understanding · not graded
Lesson check
1. Which path keeps configuration, custom code and transaction history?
2. In a new implementation, what is typically migrated?
3. Why is comparison testing central to a system conversion?
4. Which business need points toward selective data transition?