Lesson 2 of 6
Transition paths
7 min
SAP describes three main ways to get from ECC to SAP S/4HANA. They differ in what you keep (configuration, custom code, history) and how much you change. The choice is made by the program leadership, but it shapes the business's work for the whole project, so business users should understand it.
| New implementation (greenfield) | System conversion (brownfield) | Selective data transition | |
|---|---|---|---|
| What happens | Build a new SAP S/4HANA system and migrate data into it | Technically convert the existing ECC system into SAP S/4HANA | Build a new or shell system and move selected configuration and data from ECC |
| Configuration and processes | Redesigned, often from SAP Best Practices | Kept, then adjusted where simplification items require | Chosen: keep some, redesign others |
| Custom code | Rebuilt only where still needed | Kept and adapted | Selected and adapted |
| Historical transactions | Usually only open items and balances migrated; history stays in the old system or an archive | All history kept in the converted system | Chosen: for example all history, or a time slice |
| Typical drivers | Major process redesign; heavily customized or outdated ECC | Processes still fit; need for full history; time pressure | Mergers, carve-outs, consolidating several ECC systems, phased go-lives |
| Business effort | High: design, data migration, training on new processes | Moderate: validate converted data and processes, learn changes | High: decide what moves, validate both selected data and new design |
New implementation
In a new implementation, Contoso would start with a clean SAP S/4HANA system, typically using SAP Best Practices content and the SAP Activate methodology, and design its processes with fit-to-standard workshops. Master data and open items (open orders, open receivables and payables, stock, balances) are migrated; detailed history is not. The business benefit is a chance to drop years of workarounds. The cost is that every process must be re-validated and every user retrained.
System conversion
In a system conversion, IT converts the existing ECC system in place: database migration to SAP HANA, software update to SAP S/4HANA, and data conversion into the new data model (for example, customers and vendors into business partners, finance data into the Universal Journal). Configuration, custom code and all history come along. Business processes stay recognizable, except where a simplification item forces a change. This is often the fastest route, which is why it is popular under deadline pressure. It is also the path most often wrongly treated as "IT only".
Selective data transition
Selective data transition sits between the two. Typical approaches are a shell conversion (convert a copy of ECC without master and transaction data, then load selected data) or a mix and match (new installation, with chosen configuration and code transferred). It suits companies that want to redesign some areas while keeping others, consolidate several ECC systems, or bring across a time slice of history. It usually relies on specialized tools and partners.
- Do our current processes still fit the business?Yes → conversion is a strong candidate · No → consider new implementation
- Do we need full transaction history in the new system?Yes → conversion or selective transition · No → new implementation is possible
- Are we consolidating several systems or splitting a business?Yes → selective data transition is often the fit · No → continue
- Are we targeting Public Edition?Yes → new implementation only · No → all three remain options
What would you do?
Contoso's finance director insists on keeping ten years of transaction history in the new system for audit and analysis, and the operations team is happy with today's processes. Which path is most consistent with these business requirements?
- New implementation: new system, redesigned processes, open items and balances migrated.
- System conversion: existing system converted; configuration, custom code and history kept.
- Selective data transition: choose what to move; suits consolidation, carve-outs and partial redesign.
- Every path needs business validation; conversion is not "IT only".
Check your understanding · not graded
Lesson check
1. Which transition approach converts an existing ECC system, keeping its configuration and history?
2. What is usually migrated in a new implementation?
3. Which approach suits consolidating several ECC systems into one SAP S/4HANA system?
4. What is a "shell conversion"?