Why companies are moving to S/4HANA now
SAP ends mainstream maintenance for SAP ECC 6.0 and the other SAP Business Suite 7 core applications at the end of 2027. Extended maintenance is available until the end of 2030 at a higher fee. S/4HANA runs only on the SAP HANA database and brings a simplified data model, SAP Fiori user experience and SAP's current innovation.
The deadline matters, but it is not the only reason. Many ECC systems run on databases and operating systems that are themselves approaching end of support, and hardware refresh cycles often line up with the migration. Planning both together usually costs less than doing them separately.
The three transition paths
- Brownfield (system conversion): your existing ECC system is converted in place to S/4HANA. You keep your configuration, custom code and history. It is usually the fastest path when processes still fit the business.
- Greenfield (new implementation): a new S/4HANA system is built from scratch with clean-core processes, and selected data is migrated. It suits companies that want to redesign processes or whose ECC system carries too much legacy.
- Selective data transition: a new S/4HANA system receives only the configuration, organisational units and data you choose. It combines elements of both, and is often used for carve-outs, mergers or keeping only recent years of history.
The right path follows from facts about your system, not from preference. The SAP Readiness Check, simplification item checks and a custom code analysis show how much work each path involves.
Phases of a migration project
- Assessment: run the SAP Readiness Check, analyse custom code and add-ons, size the target HANA system and compare the transition paths with effort and cost.
- Planning: agree the roadmap, landscape design, downtime strategy, test cycles and cutover approach with the business.
- Preparation: clean up data, archive what you no longer need, update prerequisites and set up the target infrastructure on-premise or in the cloud.
- Technical migration: run the conversion or data load in sandbox, development and quality systems, adjusting code and configuration after each cycle.
- Testing: technical validation, performance tests, integration testing and user acceptance testing in every cycle.
- Cutover and go-live: a rehearsed production migration in the agreed window, with a tested rollback plan.
- Stabilisation: performance tuning, monitoring and support until the system runs smoothly.
SUM and DMO: how a system conversion works
For a brownfield conversion, SAP's Software Update Manager (SUM) performs the technical conversion. Its Database Migration Option (DMO) combines the move to SAP HANA with the conversion in a single run, which avoids a separate database migration project.
Downtime depends mainly on database size, hardware and the optimisation options you use. Reducing the data volume before the migration, through archiving and housekeeping, is one of the most effective ways to shorten it.
How long does an S/4HANA migration take?
Timelines vary widely with scope. A technical conversion of a single, well-maintained system with little custom code can take a few months. A large landscape with many interfaces, heavy custom code or a process redesign can take a year or more. A realistic plan comes from the assessment, not from a template.
Where to run S/4HANA
S/4HANA can run on-premise on SAP HANA certified infrastructure, on a hyperscaler such as AWS, or as RISE with SAP, SAP's subscription that bundles software, infrastructure and technical operations. Each option changes who is responsible for what, and how costs are structured. Our guide to SAP on AWS, RISE with SAP and on-premise compares them.
Common risks and how to reduce them
- Underestimated custom code: analyse it early and retire what is no longer used.
- Data quality: clean up master data before migration cycles, not during cutover.
- Too little testing: plan at least two full migration cycles before production.
- Unplanned downtime: rehearse the cutover with production-sized data and measure each step.
- Losing know-how after go-live: plan stabilisation support and knowledge transfer from the start.
Frequently asked questions
Which is better, brownfield or greenfield?
Neither is better in general. Brownfield keeps your processes and history and is usually faster; greenfield lets you redesign processes on a clean core. The assessment shows which fits your system and goals.
When does SAP ECC support end?
Mainstream maintenance for SAP ECC 6.0 ends at the end of 2027. Extended maintenance runs until the end of 2030 at a higher fee.
Can we migrate to S/4HANA and move to the cloud at the same time?
Yes. Combining the migration with a move to AWS or RISE with SAP is common, and avoids migrating twice. It needs careful planning of the landing zone and the cutover.
Written by the SAP Basis team at Farrenio. Dates and rules reflect publicly available information on 2026-11-13; check SAP's and ANAF's current terms before making decisions.