Why It’s Important to Keep Your SAP Core Clean

Firstly, let’s take a look at why your core needs cleaning.

When an organization implements a core system, it is never the case that out-of-the-box functionality delivers everything required. Therefore, developers must make additions, enhancements, and tweaks to the system to navigate the complexities of their particular IT landscape.

Other reasons for customizing include:

• Integrating with third-party systems
• Combining multiple instances following a merger or acquisition
• Creating a unique user experience or localization requirements
• Meeting regulatory requirements
• Differentiating to achieve competitive advantage

30,000 custom extensions

After a series of mergers and acquisitions, multinational health and nutrition company DSM-Firmenich was struggling with a lack of IT standardization and oversight.

This resulted in:

• A proliferation of shadow IT solutions
• Limitations in their ability to rapidly deliver enhancements
• Disparate or inconsistent systems due to localized implementations or M&A activity

“From a support perspective our historical landscape became quite hard to maintain. Every solution had its own technology with no in-house knowledge,” said Technology Development Expert Wouter Vijverberg, DSM-Firmenich.

It was a similar story at Cosun Beet (CBC), a leading sugar producer in Europe. An SAP customer since 1989, CBC had created approximately six hundred custom programs and components across two domains. Those builds and maintenance took up about 40 person-years of effort over the past 20 years.

According to ASUG, the average SAP ECC system holds more than 30,000 custom extensions to enhance SAP standard functionality. In the ASUG database are systems with custom code footprints of 100 million lines of code or more, 40%–60% of that code not even in use anymore.

So why not remove customizations?

Custom code support—not even counting changes and enhancements—can add 33% on top of a company’s SAP costs.

Over their lifespans, core systems can accumulate custom code added by a variety of different developers and team members. Inevitably, team members move on and take with them the knowledge of the whys and hows of those customizations.

There is great complexity—and cost—involved in identifying which code is no longer in use and its dependencies so it can be safely removed. Many organizations simply do not have the bandwidth or resources to do so.

Enexis is a Netherlands-based utility provider, historically reliant on custom off-the-shelf (COTS) software. When Enexis could not get what they needed from COTS options, they brought in third-party developers.

These developers would create ad hoc solutions in .NET, Java, or C++, all of which lacked any company-wide standardization or governance. Additionally, the Enexis reliance on third-party solutions and development resources left their IT team with knowledge gaps in their landscape, resulting in security challenges and issues with scaling.

Why not just leave customizations alone?

What are the drawbacks of a heavily customized system? One of the greatest challenges is the increased complexity of upgrading or migrating SAP (to S/4HANA, for example). Along with this increased complexity comes a significant increase in maintenance costs. Add to those difficulties the difficulty of maintaining the in-house skills to understand the repercussions of updating any customizations that have been made.

Swiss aircraft manufacturer, Pilatus Aircraft Ltd was very familiar with the challenges of custom SAP solutions. “When we look at our growing legacy landscape, we see a lot of custom SAP solutions and oral processes that are not documented,” said Luca De Simoni, product owner for digital operations and maintenance.

Pilatus’ legacy landscape has led to the creation of shadow IT solutions over the years. “You’ll find many different styles of solution development within the company. Excel is commonly misused in this way. Our entire legacy intranet is based on PHP. We have many .NET applications, a lot of SAP ABAP coding, and many other custom software. You’ll find a lot of non-standard solutions,” De Simoni said.

With an SAP S/4HANA upgrade on the horizon, Pilatus needed to find a way to address their challenges.

Time is of the essence

SAP has announced that maintenance support for SAP ECC will run out at the end of 2027. But for users of enhancement pack 5 or earlier, around half of all ECC customers, mainstream support will run out at the end of 2025. As a result, the advice from SAP is to upgrade to S/4HANA.

Even if you are one of the 37% of organizations that have no plans to upgrade to S/4HANA within the next two years, if at all, cleaning the core is critical for:

• Reducing maintenance costs
• Reducing complexity
• Increasing business agility
• Enabling greater innovation

Is a low-code approach the answer?

Adopting a low-code approach is the simplest solution for keeping the core clean. Low-code can help organizations quickly extend their core systems and redevelop customizations outside of the core system. SAP themselves recommend that customers use their low-code tool, SAP Build, to approach the challenge.

SAP Build is obviously tightly integrated with the SAP product suite, so it delivers benefits to the user on this front. However, when asked about their top priorities, ASUG members placed “integration between SAP and non-SAP systems” as their main focus.

SAP Build is a great tool for SAP development. But for integration of SAP and non-SAP systems?

This is where Mendix excels. Mendix can provide a far more holistic approach to helping organizations extend and modernize their core systems.

Mendix is SAP’s only Endorsed App partner for low-code and has passed SAP’s Premium Certification. With Mendix, SAP teams can reduce the time, cost, and risk barriers that make it difficult to change SAP—whether integrating after an acquisition, consolidating instances, or migrating to S/4HANA in the cloud.

Mendix is highly integrated with SAP. Customers can build apps directly on SAP HANA Cloud, deploy them directly on SAP Business Technology Platform, and integrate them with any SAP application.

Like many SAP customers, Enexis heavily customized their ERP system over the years but is now migrating to SAP S/4HANA with an aim to keep the core clean. The symbiotic relationship between SAP and Mendix makes this possible. Enexis can avoid doing custom development in SAP as this is where they will rely on Mendix. Additionally, Enexis can still extend critical SAP systems, such as in the form of reusable components to integrate project, customer, or employee data.

The Forrester TEI report on Mendix for SAP customers, commissioned by SAP, found that in comparison to users of traditional development such as SAP ABAP, SAPUI5, Java, and JavaScript, Mendix users realized:

• 8x lower development costs
• 8x shorter time to value
• Payback in less than three months

Cleaning the core with Mendix

Many organizations are using Mendix to reduce the complexity of their systems by cleaning the core.

DSM-Firmenich has a complex SAP landscape of multiple instances that uses many different tools and technologies. The company now has a Global Technology Development team supporting all custom development with Mendix, AWS, and SAP.

“We are not running on the latest version of SAP,” said DSM-Firmenich’s Vijverberg. “So the guidance from our architects is to put SAP in a box. We don’t want to change too much on SAP anymore. Instead we can use Mendix as a patch to incorporate additional functionalities.”

DSM-Firmenich has developed over 150 Mendix applications. Approximately 50% of them interact with one or more SAP instances. By using Mendix as a layer on top of multiple systems, users have a simple, single-entry point to access multiple systems. DSM-Firmenich has found solution delivery to be 5x faster with Mendix.

Developers at Cosun Beet have also found it much faster working with Mendix low-code than building SAP user interfaces. They have consolidated over 250 of their 600 customer SAP solutions so far. With just one application, their Dock Planner solution that allows staff and external vendors to book time slots at CBC docks, they save six hundred workdays per year.

Aircraft manufacturer Pilatus was able to deliver a Digital Work order (DWO) proof of concept with Mendix in just 14 weeks. “The goal [of the DWO] is to surface everything that needs to be built according to SAP, along with the corresponding drawings, documentation, 3D models, and the steps that need to be taken,” Holz said. “As tasks and orders are completed in the application, they are reflected back in the core system and updated in SAP in real-time so that Pilatus can easily see the progress on a particular aircraft and how far it is from delivery.”

Keep it clean

Whether you’re looking to upgrade your core systems or optimize your current implementation, there is no doubt that maintaining custom code is costly and hinders your efficiency, productivity, agility, and ability to innovate and compete.

Regardless of what your strategic priorities are, working towards a clean core is key. A low-code approach can get you there faster. As Guido Zeelen, solution architect at Sibelco put it, “From a business perspective, Mendix helped us to standardize the non-standard part of our business. S/4HANA is standardizing the majority of our business processes. The bits and pieces that don’t fit into that can be standardized using low-code, which is really powerful.”

If you’d like to learn more about how Mendix can help you keep your core clean, contact us.