✅ Customise strategically; excessive changes hinder SAP agility and future scalability.
🎯 Focus on simplifying processes to maintain a clean SAP core.
⚙️ Adopt SAP standard practices before considering bespoke system modifications.
🌱 Leverage SAP BTP for critical enhancements without affecting core integrity.
🚀 Executive leadership shapes a culture prioritising simplicity and standardisation.

You want your SAP S/4HANA system to perfectly fit your business – but you also know the danger of trying to tailor it too much. Striking this balance is at the heart of the Clean Core Challenge. How do you keep your ERP “core” clean and standard while still giving your organization the features it needs? As an executive, you face this strategic dilemma head-on. On one hand, customizing SAP to every whim can turn a modern platform into a tangled web of custom code, slowing you down. On the other hand, staying completely standard might feel like you’re sacrificing unique advantages. This in-depth exploration will help you navigate that fine line. We’ll discuss why organizations struggle with a clean core, the business implications of excessive customization, and how to find the right balance between standardization and customization. We’ll also connect this challenge to the “Simplify” principle of the Fast Implementation Track (F.I.T.) methodology – showing how simplification drives agility, cost-effectiveness, and long-term scalability. Finally, we’ll look at a real-world case of a global manufacturer that reaped huge benefits by prioritizing standardization (and only allowing critical customizations), and provide actionable insights for embedding a ‘Simplify’ mindset in your SAP strategy.

Ready to ensure your SAP investment delivers speed and agility for the long haul? Let’s dive in.

Understanding the Clean Core Challenge

Every SAP S/4HANA project team talks about keeping a “clean core.” In simple terms, a clean core means leaving the SAP system’s standard code untouched and free of heavy custom modifications. Your SAP system’s core remains standardized, upgradeable, and cloud-ready – which is exactly what SAP recommends for S/4HANA. By minimizing heavy customizations, companies can avoid the costly, time-consuming challenges that come with future upgrades, ensuring the ERP system stays flexible and scalable. In an ideal world, you implement SAP and stick largely to out-of-the-box processes. But in reality, keeping that core “clean” is easier said than done.

Why do organizations struggle with this? Often, it’s a matter of culture and history. For decades, businesses running SAP ECC (the predecessor to S/4HANA) heavily customized their systems to fit unique business needs. There was a longstanding belief that if you had a special requirement, the only solution was to write custom code for it. This mindset made sense in the past: customizations did provide tailored solutions. Your teams are used to getting exactly what they ask for, and many stakeholders still expect the software to bend to the business (instead of the other way around). Over time, however, all those tweaks and add-ons accumulate into a complex patchwork.

Customization creep is the result. You start with one or two enhancements; years later, you have hundreds or thousands. For example, one global manufacturer found that after decades on SAP they had about 9,000 custom “add-ons” – everything from bespoke reports to modified screens – layered onto their ERP. It’s an extreme case, but not an unusual story for large enterprises. When every division or country office asks for a slightly different process, IT ends up modifying the core system again and again. Before you know it, you’re carrying a heavy load of custom code that touches virtually every part of the system.

Another reason it’s hard to keep a clean core is the pressure to differentiate. In competitive industries, business leaders often insist that their processes are special and give them an edge. They worry that using the “vanilla” SAP process might force them to conform to a less efficient or less unique way of working. This can lead to pushing for custom development even when SAP’s standard might suffice. There’s also the simple fact that during large implementations, saying “yes” to a customization (to make a user group happy) can be easier in the moment than saying “no.” It takes strong governance – and often executive backbone – to push back and keep the solution standard.

The Business Impact of Excessive Customization

Allowing your SAP S/4HANA core to become cluttered with custom code isn’t just an IT headache – it’s a serious business risk. As an executive, it’s crucial to understand the implications of excessive customization in business terms:

• Slow, Costly Upgrades: When your system is deeply modified, every upgrade or cloud update becomes a major undertaking. Custom code can make upgrades costly and risky, often leading to significant delays. In practice, this might mean your company hesitates to adopt new SAP releases because the last upgrade was a multi-year ordeal. Falling behind on upgrades means missing out on new features and improvements that could benefit your business, or even running unsupported software if you delay too long.
• High Maintenance Overhead: Every custom feature you add is now your company’s responsibility to maintain. Non-standard configurations increase system complexity and burden your IT teams with extra maintenance. Patches and bug fixes become more complicated because you have to ensure they don’t break your customizations. The more you customize, the more your IT department essentially becomes a software development shop – maintaining a parallel codebase alongside SAP’s standard code. This translates to higher ongoing costs and risk of downtime if one of those custom pieces fails.
• Integration Challenges: SAP S/4HANA is not an island; it’s meant to integrate with other systems and new cloud services. But extensive customizations can hinder seamless integration with new SAP modules or third-party solutions. For instance, adopting a new SAP cloud product or an AI-driven add-on might be straightforward for a clean standard system, but for a heavily modified system it could require additional development to make it work. Your ability to innovate and add on digital capabilities is slowed when the core is not standard.
• Reduced Agility: Perhaps the biggest business impact is the loss of agility. Over-customized systems become unwieldy, hindering the organization’s agility and adaptability. In a fast-changing market, you need your enterprise systems to support quick pivots – whether that’s launching a new product line, adapting your supply chain, or responding to new regulations. If every change requires reworking custom code and extensive testing, your IT becomes a bottleneck to business change. Time-to-market suffers because your ERP can’t easily flex with the business.

In short, excessive customization often creates what IT experts call “technical debt.” It’s like a credit card for convenience – you get the feature now, but you pay interest on it later in the form of higher costs and slower progress. SAP themselves are strongly pushing customers to avoid this trap. They emphasize moving to a “clean core” not just as a technical preference, but as a way to ensure that you can continuously adopt innovation. As SAP CTO Juergen Mueller put it, the goal is to be “always upgrade ready” so you can consume updates and new innovations as they come. If your core is clean (meaning any extensions use stable, upgrade-safe methods), you can take SAP’s quarterly updates or annual upgrades in stride – without breaking your business processes. The result is a company that leverages its SAP investment to the fullest, instead of being stuck on an old release because “our custom mods won’t work if we upgrade.”

By contrast, a company that customizes heavily essentially locks itself out of SAP’s innovation cycle. The business falls behind competitors who stay current. This is why the clean core challenge is not just an IT project issue; it’s a strategic concern for the boardroom. It affects your agility, your costs, and your ability to harness technology for competitive advantage.

Striking the Right Balance: Standardization vs. Customization

Faced with these risks, the intuitive response might be: “Let’s enforce zero customizations.” In reality, it’s about finding the right balance. Some level of customization may be necessary – even beneficial – but it must be approached with caution and strategic intent. As an executive, you need to guide your organization in balancing the benefits of SAP’s standard best practices with the need to tailor the system for genuine business advantages.

Start with the principle that standard is the default. SAP S/4HANA comes with built-in processes based on industry best practices. In many cases, these out-of-the-box processes will cover 80-90% (or more) of what your business needs. Embracing them can actually be an opportunity to improve and streamline your operations, leveraging the experience coded into SAP. For the remaining gaps, carefully evaluate if they truly require custom development. If a standard solution meets, say, 98% of your requirements, it’s usually better to adopt it and adjust your process for the other 2% than to reinvent the wheel for a “perfect” fit. In other words, don’t let the perfect be the enemy of the good – especially when “perfect” comes with a hefty price in complexity.

SAP’s recommended approach for new implementations is tellingly called “Fit-to-Standard.” This approach flips the old mindset: instead of asking “How can we customize SAP to do exactly what we do today?”, you ask “How can we adapt our business processes to the way SAP software works out of the box?” Fit-to-Standard is a mindset that requires looking hard at what’s already available in SAP before creating something from scratch. It might involve some business process changes or compromise on non-critical preferences, but it keeps the solution clean and future-proof. For example, if the standard SAP order-to-cash process is slightly different from your legacy process, consider adjusting your process to SAP’s model. If needed, tweak configurations (which are upgrade-safe) rather than writing new code.

Of course, there will be cases where the standard doesn’t cover a crucial requirement. The key is to differentiate between what’s truly strategic for your business and what’s merely habit or minor convenience. If a process directly underpins your competitive advantage or is necessary for compliance, it might justify an extension or customization. Even then, the goal should be to keep the core clean while extending functionality. SAP provides modern ways to do this – for instance, using the SAP Business Technology Platform (BTP) to build extensions side-by-side without altering the core system’s code. That way, you can have custom functionality where it really matters, but because it’s decoupled from the core, you retain the ability to upgrade and innovate. SAP’s clean core strategy explicitly encourages this: move custom business logic to external, upgrade-friendly extension platforms and keep the S/4HANA system itself as standard as possible.

Practical tip: Establish a clear governance process for customization requests. Many successful SAP programs set up a “Design Authority” or Solution Review Board that evaluates each requested customization. As an executive sponsor, you can mandate that any deviation from standard go through a rigorous value assessment. This board should ask: Does this change drive substantial business value or competitive differentiation? Is there a way to meet the need with standard configuration or process change? Often, just having this checkpoint causes project teams to think twice and avoid knee-jerk customizations. It also sends a message that staying standard is the company’s expected approach, unless a strong case is made otherwise.

Another way to balance standard vs. custom is to consider a tiered model. Some large enterprises adopt a “core and edge” strategy: The core ERP handles common, standardized processes (which are kept clean), while more unique or innovative capabilities are developed at the “edges” – perhaps in satellite systems or cloud applications that integrate with the core. With S/4HANA, this could mean using cloud services or microservices for experimental or highly specialized functions, rather than building them into the ERP. This ensures the core remains stable, while still giving the business flexibility to innovate.

The bottom line is to customize consciously. When you allow a customization, do it in a way that you can live with for the long term. Make sure there is a plan for how that custom piece will be maintained through upgrades or eventually retired if SAP delivers that capability in a future release. By finding this balance – standard wherever possible, custom only where it truly counts – you position your SAP environment to deliver both reliability and adaptability.

Simplify: The F.I.T. Philosophy in Action

One powerful framework to help enforce this balance is the Fast Implementation Track (F.I.T.) methodology, particularly its “Simplify” component. F.I.T. is a mindset for SAP projects that emphasizes focusing on what really drives value and cutting out the noise. In the context of the clean core challenge, “Simplify” is about consciously resisting the allure of excessive customization. It’s a call to keep things simple, smart, and aligned with standard best practices.

You probably know how easy it is for an SAP project to become over-engineered. Everyone wants a tweak here and an extra report there – it’s like a kid in a candy store. The allure of customization can be intoxicating, but it’s also where projects go off the rails. The Simplify principle reminds us that less is more. It champions sticking with standard SAP functionality and only customizing when there’s a solid business reason. In practice, that means as a leader you encourage your team to ask at every juncture: “Do we really need this customization? What is the simplest way to achieve our goal?” Often, a simpler, standard solution exists – and choosing it will save time, money, and headaches later.

Crucially, simplifying is not about cutting corners or delivering a bare-bones system. It’s about avoiding unnecessary complexity. As the F.I.T. guidance puts it, stick with standard practices and customize only when it’s absolutely justified. When you do this, you deliver a straightforward, effective solution that users can actually understand and adopt, and that doesn’t require a 300-page manual or constant IT firefighting. In fact, delivering a system that is easy to use and maintain will make you “look like a genius” to the business, because it works without drama.

Adopting the Simplify mindset yields tangible benefits for the business: speed, agility, and cost-effectiveness. If you avoid over-customizing, your implementation itself will likely finish faster (since custom development and testing are often what slow projects down). You’ll also find that with fewer moving parts in your solution, you can respond to new requests or changes more quickly. Need to roll out a new process template to a region? It’s easier when you don’t have to untangle custom code in the core. Want to take advantage of a new SAP S/4HANA feature or a cloud integration? It’s feasible when your core is clean enough to be updated with minimal effort. Simplification directly enables agility – the organization can pivot or scale without being handcuffed by a rigid, complex system. Moreover, staying closer to standard keeps your TCO (total cost of ownership) down. You’re spending less on custom development and maintenance, and more of your IT budget goes toward forward-looking improvements rather than “keeping the lights on” in a convoluted legacy of custom code.

It’s also worth noting the long-term scalability that Simplify provides. A simplified core means you can scale your SAP footprint (adding new modules, integrating acquisitions, expanding to new geographies) with far less friction. You’re essentially building on a solid, clean foundation. Just as importantly, when disruptive technology waves come – think AI, IoT data, advanced analytics – your clean core is ready to plug in those innovations quickly. SAP’s CTO highlights that companies with a clean core can “continuously adopt updates and new innovations” as SAP rolls them out. The more you simplify now, the easier it becomes to multiply your capabilities later by leveraging the latest tech.

So, how do you put Simplify into action? It starts as an ethos you instill in the project team: challenge complexity at every turn. Encourage open discussions where team members feel safe questioning whether a feature is truly needed. Celebrate solutions that achieve outcomes with clever use of standard tools rather than custom code. As an executive, when you review project status, ask pointed questions: How are we keeping the core clean? Have we tried to use what SAP provides here instead of custom coding? When your organization sees that leadership values simplicity and will back them up when saying “no” to superfluous features, they’ll be empowered to adhere to that principle. Simplify, in essence, is about having the discipline to deliver exactly what the business needs – and nothing more – so the result is elegant, efficient, and future-ready.

Executives at the Helm: Driving a ‘Simplify’ Mindset

Achieving a clean core and a balanced approach to customization isn’t just an IT task – it’s a leadership challenge. As a boardroom executive or project sponsor, you have the influence to set the tone and drive a ‘Simplify’ mindset across the organization. Here are some actionable ways you can champion this approach:

• Set Clear Policies and Governance: Establish upfront that the project’s mandate is to “configure first, customize second.” Make it company policy that any customization must come with a compelling business case and obtain approval from a high-level design authority (which you or your delegate oversee). This governance creates healthy friction – teams know they can’t just build custom solutions on a whim. By requiring a solid justification, you ensure custom development is reserved for genuinely critical needs. For example, you might require sign-off from the CFO or CIO for any custom enhancement that touches core finance or logistics processes. This level of oversight signals how serious you are about keeping the system clean.
• Champion Standardization from the Top: Use your platform to encourage business units to adapt to standard SAP processes rather than adapt SAP to existing processes. This often means investing in change management and user education so that employees understand how the new standard process works and why it’s beneficial. When people resist changing a process, back up your project leads in asking “why not give the SAP way a try?” Show them successful cases or benchmarks of companies thriving with standard processes. When executives consistently reinforce the message that standard is not just “okay” but often preferable, it helps shift the culture. Essentially, you are influencing company culture to align more closely with standard SAP – turning “that’s how we’ve always done it” into “let’s adopt industry best practices.”
• Insist on Modern Extension Methods: When customization is unavoidable, ensure the solution architects use approaches that preserve the clean core. For instance, push for use of SAP’s extensibility options like the Business Technology Platform (SAP BTP) or other side-by-side extension frameworks, instead of hard-coding changes into S/4HANA itself. By building extensions “on the side” and integrating via APIs, you get the needed functionality without altering the core code. This was the approach used by Hitachi High-Tech in their transformation – they kept S/4HANA standard and built required custom apps on SAP BTP, which allowed for faster upgrades and immediate access to improved functionality. As an executive, you don’t need to get into the weeds of how ABAP or APIs work, but do ask your IT leadership: “Are we using side-by-side extensions? Will this feature work if we upgrade SAP?” By asking these questions, you reinforce the expectation that no fix is worth breaking upgradeability. In turn, your architects will design solutions with upgrade-safe, clean principles (because they know leadership cares).
• Emphasize Long-Term Value Over Short-Term Convenience: It’s easy for project teams to justify customization by saying it will make life easier for users in the short run. Your role is to broaden that perspective. Continuously frame decisions in terms of long-term agility and total cost. For example, if a team wants a custom workflow for a minor approval process, ask them to consider the maintenance cost and potential rework needed every time you patch or update the system. Sometimes quantifying this helps – “Yes, we can build that feature, but it might add 3 weeks to every future upgrade cycle and $50k/year in upkeep. Is it worth it?” By forcing this kind of dialogue, you encourage everyone to think beyond the immediate project go-live. Remind stakeholders that every customization is not just a one-time build – it’s a long-term commitment. When business leaders hear that message from their executive peers, they are more likely to prioritize what truly matters.
• Lead by Example and Highlight Successes: Your own engagement and communication can powerfully shape the project ethos. Make a point to celebrate simplification victories. Did the team decide to use a standard Fiori app instead of building a custom UI for a process? Give them a shout-out in the steering committee for saving time and safeguarding future upgrades. If a particular department agreed to change a legacy process to fit SAP standard, acknowledge their flexibility and explain how it benefits the company’s agility. Moreover, share success stories – like the case of the manufacturer we’ll discuss next – with your peers and project teams. Show them tangible proof that sticking to standard and simplifying pays off. When people see that executives recognize and appreciate decisions that avoid unnecessary complexity, they’ll be more motivated to follow suit. In essence, you’re setting a precedent: simplicity is a virtue, not a sacrifice. And by fostering that mindset, you position your SAP project (and the business) for smoother sailing in the years to come.

By taking these actions, you transform the abstract idea of “Simplify” into daily decision-making on the project. Your leadership ensures that the entire team – from consultants to business analysts – feels empowered to prioritize long-term value and elegance over short-term fixes. It’s a strategic investment in the future health of your SAP landscape. And as the next example shows, that investment can deliver substantial returns.

Case in Point: A Global Manufacturer’s Clean Core Transformation

To truly appreciate the benefits of prioritizing standardization (and limiting custom work to what’s critical), let’s look at a real-world example. Hitachi High-Tech, a global manufacturer and decades-long SAP customer, recently undertook a major transformation that embodies the “clean core” philosophy. Their journey offers a blueprint of the challenges and the payoff of getting this balance right.

The starting point: Hitachi High-Tech had been running SAP ERP since the 1990s to support its worldwide business. Over the years, as often happens with long-time SAP users, they had built up a huge inventory of custom code on their system – around 9,000 custom add-ons by the time they were considering a change. These add-ons ranged from custom reports and input screens to deep modifications for complex manufacturing processes. In the earlier era, this level of customization had helped tailor the system to each region’s needs. But by the 2020s, the weight of those 9,000 modifications had made the system unwieldy. It hindered the company’s agility and adaptability. Essentially, their ERP had become so customized that introducing any new process or upgrading to a newer SAP version was incredibly slow and painful. They realized that carrying this “baggage” forward would only hold them back in a fast-moving tech environment.

The bold decision: Instead of trying to tweak the existing system, Hitachi High-Tech leadership opted for a “clean slate” approach with SAP S/4HANA. They chose a greenfield implementation – meaning they started fresh with a new S/4HANA system, rather than migrating all the old processes and code over. This was a brave move for a large, complex enterprise, but it was driven by a clear vision: speed and simplicity. The company’s mission statement even emphasized “a simplified customer process,” which set the tone from the top. By going greenfield, they gave themselves the opportunity to redesign processes and only build what was truly necessary for their business going forward. In other words, they weren’t going to simply re-implement those 9,000 add-ons; they would justify each piece of functionality anew or drop it if it wasn’t vital.

Implementing a clean core: During the S/4HANA project, Hitachi High-Tech rigorously applied the principles we discussed. They standardised and simplified processes wherever possible and leveraged SAP’s modern extension tools for any needed enhancements. The results were striking – they slashed those 9,000 legacy customizations down to about 800 in the new system. That’s over a 90% reduction in custom code! How did they manage that? First, many old custom reports or forms were no longer needed thanks to improved standard analytics in S/4HANA. Secondly, for the custom capabilities they did need, they built most of them side-by-side on the SAP Business Technology Platform (BTP) rather than as modifications in S/4HANA itself. This meant the core S/4HANA application could remain largely untouched (clean), with custom apps and extensions running on BTP and connecting via interfaces. By not altering the core code, they safeguarded the system’s stability and agility.

One telling detail: after moving to S/4HANA, Hitachi High-Tech completely stopped developing new add-ons in the core system. All new needs would be addressed either with standard functionality or built on the side. This discipline ensured they wouldn’t fall into the same trap again. Takuya Sakai, a general manager leading the transformation, highlighted that “Side-by-side development on SAP BTP… allows for faster upgrades, giving our people more immediate access to improved functionality.” In other words, by keeping enhancements decoupled from the core, they can take SAP’s upgrades practically as soon as they come, because there’s little or no rework needed on custom code. This is a huge win – it means IT can deliver innovations to the business much faster than before.

The tangible benefits: The impact of this clean core approach at Hitachi High-Tech has been dramatic. In the past, their heavily modified system could only be upgraded every 7 to 10 years (a common fate for highly customized ERPs), and each upgrade was a massive project – taking on the order of a year and a half to execute, with significant testing and downtime. Now, with S/4HANA and a clean core, they are able to upgrade every year (or with each new SAP release) and an upgrade takes roughly six weeks. Let that sink in: from an 18-month disruptive upgrade project down to a six-week routine exercise. This kind of agility is transformational. It means the company is always on a modern version of SAP, with access to the latest features to support the business. The risk of falling behind or running an obsolete system is gone. Sakai noted that moving from an increasingly customized, cumbersome legacy system to a clean-core S/4HANA environment gave them new flexibility, speed, and stability. In practical terms, they’ve boosted the speed of their business operations and IT responsiveness to a level that would have been impossible with the old approach.

Additionally, because all their offices worldwide are now connected on this new platform (with common standard processes), Hitachi High-Tech gained better visibility and consistency across the organization. This is a secondary benefit of standardization: it enforces a common way of working, which makes it easier to share data and insights globally. They’ve essentially achieved a more agile enterprise architecture – one that can evolve without huge overhauls.

The Hitachi High-Tech case illustrates that the clean core approach isn’t just theoretical – it delivers real business value. By prioritizing standardization and only allowing critical customizations (in a controlled way), they reduced IT complexity and unlocked agility. It required forward-thinking leadership to take that path. Executives had to be willing to discard old, familiar custom solutions and trust in SAP’s standard capabilities. They had to unite IT and business teams around new processes. But the payoff was clear: a faster, leaner, more future-proof platform to run the business. Their story serves as a compelling proof point to any executive wondering if a simplify-and-standardize strategy is worth it. In this case, less truly became more – less custom code, more business agility.

Conclusion & Call to Action

The journey to a clean core in SAP S/4HANA is as much about leadership and mindset as it is about technology. You’ve seen why organizations struggle with letting go of customizations, and the heavy price they pay when they don’t. You’ve also seen that there is a path to balance: by staying standard wherever possible and carefully controlling necessary custom work, you can have the best of both worlds – a system that meets your business needs and stays nimble, cost-effective, and ready for the future. Embracing the “Simplify” principle is your key to unlocking that balance. It means fostering a culture where adding complexity is the last resort, not the first instinct. It means steering your SAP projects with a strategic eye, always weighing the long-term impacts of today’s decisions.

As a boardroom executive, your role in this cannot be overstated. The direction you set will ripple through project teams, implementation partners, and end-users alike. If you champion a clean core and a simplify mindset, others will follow. The payoff isn’t just technical elegance – it’s the agility of your business, the speed at which you can seize new opportunities, and the efficiency of your operations for years to come. Think of your SAP S/4HANA like the foundation of a skyscraper: if it’s solid and clean, you can keep building higher confidently. If it’s full of cracks (or hacks, in the case of software), every new floor is risky and expensive.

So, take a moment to reflect on your own SAP strategy. Is your S/4HANA core as clean and streamlined as it should be? Are you leveraging the power of SAP standard solutions, or inadvertently rebuilding solutions you already own? Perhaps it’s time to convene your team and assess: what can we simplify, what custom baggage can we let go, and how can we better architect our system for continuous innovation? The Clean Core Challenge is real, but it’s a challenge you can overcome with the right approach and leadership resolve.

Ultimately, keeping a clean core is an ongoing discipline, not a one-time task. It requires vigilance and a commitment to the “less is more” ethos even after go-live. Yet the reward is an ERP platform that empowers, rather than impedes, your business strategy. As you move forward with your SAP initiatives, remember the lessons from those who have navigated this journey successfully. Simplify where you can, customize only when you must, and always with an eye on the future.

Call to Action: Take stock of your SAP environment today. Rally your stakeholders around the idea of simplification as a strategy, not a sacrifice. Encourage your IT and business teams to identify one area where you could replace a custom solution with a standard one, or streamline a complex process. Small wins build momentum. After reading this, how will you apply the ‘Simplify’ principle to your SAP projects and products? In the next board meeting or project review, pose this question: Are we truly keeping our core clean, and what more can we do to embrace simplicity for the sake of agility and growth? The answers could very well shape the future success of your SAP investment – and your business. So, how clean is your core, and what steps will you take to simplify and strengthen your SAP strategy moving forward?

A high-level illustration of the Clean Core concept in SAP S/4HANA. On the left, a heavily customized on-premise ERP has many grey “custom process” blocks embedded in the core. In the middle, during transition to S/4HANA, there are still some custom elements, though reduced. On the right, the Clean Core approach moves custom processes out of the core into SAP Business Technology Platform (indicated at the bottom), leaving the S/4HANA core clean (all blue). Keeping modifications separate from the core ensures easier upgrades and a more robust, scalable system.