Many organizations are still considering or in the process of conversion to S/4HANA. The road map for this complex project is fairly well-defined at this point. However, we recommend taking a closer look at the plan with functional and technical experts to validate the business case and fine-tune the scope, focus, and project plan.
Why Is It So Complex?
The move to S/4HANA is not like previous system upgrades. It’s a complete platform change that impacts every area of the business – from finance and logistics to HR and manufacturing. What’s more, it’s not just a technology upgrade. The new functionalities and processes need to be designed and configured to take advantage of the underlying technology. This requires new skills and knowledge across the organization.
Upgrading to S/4HANA will allow organizations to simplify their IT architecture, access the business suite enhancements as possible, and implement Fiori for all their users with their own apps. But before making such a significant investment in time and effort, it’s critical to ensure that experts who understand the state of the current systems and current ways of working are involved in planning out all required activities.
Business Case Validation Is Critical
Depending on the size and complexity of your organization, you may have multiple systems running on different versions of SAP software. These systems need to be integrated into a cohesive whole that takes advantage of all that S/4HANA offers in terms of functionality, performance, security, etc. To do this right, you need consultants or experts who has done it before and who understand both the current state of your systems as well as how they fit within your overall business operations. Validating the business case with functional and technical experts will help ensure that you have a realistic project plan that considers all required activities – from data migration and system integration to user training and testing. This may lead to an adjustment of the plan for improved scope, more refined focus, and a more realistic project plan.
Conclusion: Implementing S/4HANA requires much more than just upgrading your technology. It’s a chance to simplify your IT architecture, take advantage of new functionalities and processes,and improve the way you work. But because it’s such a complex project, you need to make sure that you have expert help in order to create a realistic plan that takes into account all required activities necessary for a successful conversion. Failing to do so could jeopardize the entire project – not to mention your job!
(First article from a series of articles focusing on S/4 HANA Conversion)
The three paths to S/4HANA, honestly compared
Every conversion conversation eventually lands on the same fork in the road: brownfield, greenfield, or selective data transition. Each is legitimate. Each has a personality, and picking the wrong one is where most of the pain stories start.
Brownfield (system conversion) keeps your existing configuration and converts the technical platform underneath it. It is the fastest path and the least disruptive to the business, which is why most ECC customers choose it. The trade-off is that you carry your legacy processes, your custom code, and your historical compromises into the new world. Brownfield is a technical project with business implications, and teams that treat it as purely technical are the ones that end up with a shiny new system running twenty-year-old workarounds.
Greenfield (new implementation) starts from a clean S/4HANA system and reimplements processes using SAP best practices. It is the best way to actually simplify and modernize, and it pairs naturally with a business transformation agenda. The trade-off is time, cost, and change: you are asking the business to adopt new processes while migrating data and retraining everyone. Greenfield done well is transformative; greenfield done without executive stamina becomes a multi-year odyssey.
Selective data transition sits in the middle: keep what works, redesign what does not, consolidate landscapes selectively. It offers the most flexibility and the most complexity, because the scope is bespoke. This path demands the most experienced architects, since every selective decision is a custom engineering choice. For companies with multiple ECC systems or carve-out scenarios, it is often the only sane option.
The honest advice: match the path to your actual appetite for change, not to the one with the prettiest slide deck. A company that cannot get its business leaders into a room for process redesign should not pick greenfield, no matter how attractive the best-practice story sounds.
Where conversions actually fail
The failure modes are well documented because they keep repeating. Custom code is the famous one: the average ECC system carries years of custom objects, and typically a quarter of it is never even executed. The Simplification Item check and the ABAP Test Cockpit custom code analyzer exist precisely to triage this, but the remediation work still needs experienced ABAPers who can tell the difference between code that must be rewritten, code that can be retired, and code that can be replaced by standard functionality.
Data migration is the quiet killer. Cleansing, mapping, and validating master and transactional data almost always takes longer than planned, and it cannot be compressed at the end without consequences. Testing is chronically under-scoped: teams test the happy path, go live, and discover the month-end close process nobody documented. And the meta-failure is governance: treating the conversion as an IT upgrade instead of a business program, which means no one with authority is making the hard scope decisions until they become emergencies.
A readiness checklist before you sign the SOW
Before committing to a conversion partner and a timeline, make sure you can check these boxes:
- The business case is written in real numbers, validated by finance, not just IT efficiency claims.
- A Simplification Item review has been run against your actual system, not a generic list.
- You have an inventory of custom code with a first-pass triage: keep, remediate, retire, replace.
- Master data quality has been baselined, with owners assigned for the cleanup.
- A sandbox conversion has been attempted, so the timeline is based on evidence, not optimism.
- The resource plan names real people, including backfill for the business users who will be pulled into the project.
- Governance is defined: who decides scope disputes, and how fast.
That last item is the one most often skipped and most often regretted. An S/4 conversion without a clear decision-maker is a very expensive way to hold meetings.
