Enterprises are inching towards the support deadline for SAP ECC, which is approaching in 2027, and many are realizing that the path to S/4HANA is less about putting a Band-Aid on the problem. This is more about ensuring the vast array of custom developments remains compatible and performant with future S/4HANA upgrades. The shift is making enterprises adopt “clean core” strategies, which describe a system or landscape of systems that is as close to standard as possible while running cloud-compliant extensions and integrations.
What’s the Objective of Clean Core?
The object of clean core is to run SAP S/4HANA with minimal modifications to the underlying system code. Rather than embedding custom logic deep within the application layer, clean core retains any customizations businesses have made through SAP Business Technology Platform (BTP), side-by-side extensions or cloud-native APIs. The approach preserves the integrity of the core ERP, ensuring it remains upgrade-friendly and compatible with SAP’s innovation roadmap.
In short, a clean core is not about losing customization, but about decoupling business-specific enhancements from SAP’s core so that businesses can keep the pace of innovation without sacrificing operational stability.
Cleaning Up Costs
In a clean-core environment, upgrades are deployed with much less friction and fewer regressions compared to custom-heavy legacy systems. Technical debt is reduced, as removing the embedded custom code reduces the overhead associated with testing, refactoring and manual upgrades. For businesses, the total cost of ownership is lower for clean core systems, which in turn have fewer future surprises and lower costs over time between infrastructure and development.
To ensure the business stays on the edge of technological tools, employees and innovators must be given the tools to innovate. Clean core systems’ technological capabilities expand with releases from SAP as soon as they arrive on the marketplace. This positions the business and the employees for success on the latest and greatest tools and makes innovation a cornerstone of business. Clean core organizations must embrace SAP’s continuous delivery model and work at the pace of today’s rapid innovations.
Up Against ABAP Legacy
More complex global operations translate into a higher likelihood that an enterprise faces deep customization legacies in an ECC environment. Years of ABAP code embedded in legacy ERP make the clean core journey a difficult overhaul. What was once a stalled migration now leads to technical debt, putting enterprises at a major risk. Migrating heavily customized code into S/4HANA RISE will lead to high costs, compatibility issues, and stalled upgrade cycles in the long run.
In day-to-day operations, achieving clean code demands teamwide efforts to shift the audit customizations, determine business value and refactor or retire outdated code. In the long term, leaders must be serious about implementing and accepting changes to organizational culture. Business users and IT teams can no longer “build everything inside,” but instead build with extensibility and composability in mind. SAP provides the tools to support this transition, but the strategic alignment must come from leadership.
Implementing Clean Core Made Easier
Implementing clean core is not a one-time event but should be a roadmap that begins with transparency. The first step is to audit and catalogue the customizations in your current SAP ecosystem. Then, step two, teams must evaluate each customization against three criteria:
- Is this custom component still necessary for the business?
- Can it be achieved with standard SAP functionality today?
- If custom, can it be moved to BTP or other decoupled architectures?
Step three is to prioritize remediation. Large organizations often take a phased approach, applying clean core principles first to foundational modules (e.g., finance, procurement), then gradually expanding to other departments. Depending on the business and the migration job, SAP’s Custom Code Migration App and third-party code analysis platforms can usually accelerate the analysis-heavy steps.
Then, there are the ongoing moving parts of any system — maintenance and governance. Establish controls that prevent reintroducing code into the core post-migration. Every enhancement request from thereon should follow a “clean-core-first” policy. The motto should be “cloud-first, decoupled by design.”
Business Agility Beyond IT
Clean core does not just serve IT’s interests but will directly impact business agility across teams. For example, when a company divests or launches a new line of business, clean core allows for faster spin-up or carve-outs. During supply chain shifts or regulatory changes, clean core systems pivot more readily with fewer disruptions to the business since the shift is accounted for in the system. The clean core model gives companies a modern ERP that keeps pace with business growth and strategically positions the company to stay a few steps ahead.
In VASS’s work with clients across industries, we have seen clean core principles drive cross-functional alignment. The ability to plan, test and execute changes with confidence reduces friction in business functions across teams. To name a few departments, typically finance, procurement, compliance and IT all see the greatest benefits from increased system predictability, fewer unplanned outages and reduced operational drag throughout digital transformation.
What to Do Before December 2027
As the deadline for ECC support looms, organizations are rightly focused on the transition to S/4HANA. But this challenge shouldn’t be treated as a software upgrade. This is a huge opportunity for businesses to rethink what systems are outdated and how to prepare for future SAP features. Clean core must be a cornerstone of that strategy, as it proves composability, cloud compatibility and long-term ROI time and time again.
Clean core is not only the best practice, but the new baseline for transformation-ready business systems. To get started, enterprises must identify all their custom ABAP objects (reports, interfaces, conversions, enhancements, forms, workflows — RICEFW), analyze for S/4HANA compatibility, and then create a plan for what goes where in the migration. For enterprises with a heftier legacy code and more to analyze, or those who are too overwhelmed to know how to start, simply look to the market to find a trusted partner. But do not wait until November of 2027 to begin this process. Enterprises that invest in clean core now will unlock smoother migrations and gain a permanent edge in adaptability.
