“Clean Core” is one of the most discussed topics around SAP S/4HANA—and at the same time one of the most frequently misunderstood. Many companies ask themselves: Do we now have to throw away everything we have built up over the years?
The short answer: No. But it is worth taking a closer look.
What does Clean Core mean?
Clean Core means keeping the SAP core free of modifications. Instead of adapting core code—which makes updates more difficult, increases upgrade costs, and jeopardizes system stability—extensions are implemented via official SAP mechanisms: released APIs, BAdIs, or extensions on the Business Technology Platform (BTP).
The goal: an SAP system that remains updateable, low-maintenance, and future-proof.
Why is this particularly relevant right now?
With the end of mainstream support for SAP ECC, many companies are facing migration to S/4HANA. Anyone who drags along their accumulated mountain of modifications pays twice: once during the migration, and again with every update thereafter.
Clean Core is not a nice-to-have—it is the foundation for ensuring that S/4HANA remains economically viable to operate in the long term.
The first step: knowing where you stand
Many companies do not even know how many modifications they actually have—and how critical they really are. This is not a failure, but the result of systems that have grown over many years.
The first concrete step is therefore always: enable and evaluate the Clean Core analysis in your own system. Only then does it become clear what you are really dealing with—and what is truly urgent.
In our experience: not every finding is the same. The total number often sounds alarming. The truly critical cases are usually significantly fewer—but they are serious.
Three common mistakes we see in projects
Modifications are carried over without reflection. Without checking whether the SAP standard now offers the same function. In many cases it does—the custom development is simply no longer necessary.
Custom developments end up in the core. Even though side-by-side extensions or BTP would be the better choice. Often out of habit, sometimes due to time pressure.
Clean Core is understood as a one-off task. In fact, it is a continuous approach. Anyone who cleans up once and then continues as before has not internalized the principle.
What we have learned ourselves
At secat, we are currently taking this path ourselves with our own product QPPD. When we first subjected our codebase to a full Clean Core review, we were faced with nearly 9,000 critical findings.
What helped: a structured approach, automated analysis, prioritization—and not trying to tackle everything at once. The biggest technical challenge was replacing classic SAP GUI technologies such as ALV Tree and ALV Grid, which we replaced with UI5.
We are not finished yet. But we know exactly what each phase of this process feels like—and what truly helps.
How secat supports you
We support companies on the Clean Core journey—from the initial analysis through to concrete implementation. With packages that are clearly defined and start without hidden follow-up costs:
- Clean Core Assessment (3–5 days, remote): We enable the analysis in your system, evaluate the findings, and present the results to you.
- Clean Core Roadmap (5–10 days): Based on the assessment, we develop a prioritized roadmap with a realistic effort estimate.
- Clean Core Quick Win (from 5 days): Together, we replace a specific modification—from selection through handover.
👉 More about our Clean Core packages
Would you like to know where your system stands? Get in touch—the first step is easier than you think.