The global and independent platform for the SAP community.

A Clean Core for S/4

Existing SAP customers want to map new processes in their ERP systems. In most cases, they have written all individual enhancements directly into the core system, thus building unique capabilities into the systems.
Maximilian Krcmar, cbs
May 2, 2023
This text has been automatically translated from German to English.

Of course, you can customize the SAP system and build your own developments. I have to extend processes, integrate http bodies, add my own fields and implement my own logic for certain processes. But very quickly I reach a point in the projects where customizing leads to a dead end. So it seems advisable to me to introduce the Business Technology Platform (BTP) before an S/4 project. When customizing, I move further and further away from the SAP standard - and that's not smart. After all, all these enhancements must somehow be carried over when a new software upgrade, a release upgrade or a move to a new system is due. 

With every update, I have to touch these special extensions individually, adjust them, examine them in particular, test them several times and virtually rewrite them. A huge effort. If I don't do this, errors, so-called "defects", occur immediately. Also, one should not use elements from SAP that are not released, since these can change just like the standard.

Clean Core means Lean Core

The answer is simple: Keep your core clean. Keep your core clean. What does Clean Core actually mean? Clean Core is an important approach to software development that aims to keep core systems as clean and tidy as possible. This approach focuses on the quality and maintainability of the core system by ensuring that the core area is well structured and easy to understand.

Clean Core also means that the SAP core is truly free of any hard modifications. From extreme individual logics and body implementations and from completely unique Z-logics. Because: In the operating concept of S/4 Hana, such extensions are simply no longer provided for. Third-party add-ons that are connected via cloud software no longer fit either, because they require a certain standard that has been delivered by SAP.

Existing SAP customers who are using a "dirty" core are faced with many problems. Manual detail work becomes necessary and thus an immense time delay in projects. And possibly even a security gap can arise.

20 years old extensions

Whereby, Clean Core is actually not correct, the core was not dirty before, but you have created dependencies that slow you down looking forward. So let's talk about Lean Core. Lean Core. So it's elementary to simplify your upgrade processes, to speed them up and make them more secure overall.

Let's look at what was before S/4. Often, different ERP systems are consolidated into one ERP. Some of these systems originate from acquisitions, some from different countries with different guidelines for in-house developments. If I now consolidate all of this into a new S/4 system, it naturally becomes difficult to maintain an overview and keep the whole thing maintainable.

Then it's high time to rethink your entire extension strategy. Many extensions have been running for 15 or 20 years, but no one has documented them properly. The originators are often no longer even in the company. In some cases, documentation has simply been lost. But if I no longer have the logic behind a calculation in the financial system, I can quickly get into trouble when the auditor comes. The world is in a state of upheaval, the market is changing in ever shorter cycles, so that the global players can no longer get anywhere with classic, static extensions from the old days. Pandemics, climate change, political upheavals, supply chain bottlenecks, inflation, cyber attacks, energy crisis and the quest for sustainability - multi-layered challenges that need to be solved.

The next generation

In addition, the digital transformation must be mastered. New business models must be integrated. New digital assets must be built that enable companies to keep pace with growing customer demands. IT departments are expected to build the next generation of enterprise solutions (Next One) - which can be used to respond more agilely to new conditions and implement new technologies more quickly.  

The SAP Business Technology Platform, BTP, is ideal for precisely these innovations because it offers a wealth of options and is simply very close to the SAP core, but customers can also theoretically use Microsoft Azure. I always tell my customers: You also have an API business hub that allows you to always access the SAP system and exchange data at will. This SAP cloud integration is a Platform as a Service that enables smooth integration of on-prem and cloud-based applications and processes with SAP-managed tools and preconfigured content.

Industry knowledge, special process know-how, industry expertise - there's a lot in your own coding. With the Business Technology Platform, I can protect my investment perfectly. It's the Z enhancements that should be made to the BTP in the future. Our message: You know the Abap world (Advanced Business Application Programming), since 1990 all SAP R/3 modules are based on this language, but now you have the unique chance to experience a technological evolutionary leap in development.

We therefore want to bring you up to date: What makes SAP tick? How does an S/4 system behave in terms of extensions? What can you actually do with the BTP? The new SAP world is different, so customers have to change, too. My advice: Even if you don't switch to S/4 for another two years, familiarize yourself with the BTP today.

Often the customer then decides to buy a few licenses to get a first impression of the look-and-feel of the BTP. He can then start a proof of concept (PoC), for example, and map a standard transaction from SAP ERP/ECC 6.0 or a classic Z extension via the cloud platform.

Complexity increases

However, one must be clear: The BTP is initially just an empty shell. It will be a long time before I can provide a business application that I can really use productively, an application that meets my company standards and creates added value.

This means: If I only start my agile developments when S/4 is already going live in the company, that's pretty late. Perhaps too late. Because then I'm already technologically behind from the outset. 

I often explain it to customers like this: We have a small project in the S/4 program - we can start with that earlier. Then we are prepared for the requirements that come from the business during the S/4 project and that we have to implement in an agile manner. After all, the BTP is not a small gadget in a niche, it's not a "nice-to-have", but a powerful machine with enterprise applications that need to be up and running as quickly as possible. And sometimes it may even map core processes of the company.


Do we have to be afraid of an almost confusing mix of hybrid technologies in the future? There are Abap extensions, in-app customizations, side-by-side extensions, plus on-prem and cloud solutions coexisting, and, and, and. We see Abap specialists and cloud developers side by side - and sometimes I have a third developer who has developed the UI (user interface). That's where the complexity around the ERP increases significantly. And it has to be mastered. It's no longer just a small group of people who have mastered the full spectrum of programming languages and interfaces; there are more people and roles involved. 

The goal must be to better organize responsibilities so that I can secure future updates without having to do customizing in the core system.

I think it is advisable to stay as close as possible to SAP guidance, to include new technologies early in your 2023 and 2024 planning, even if that requires a radical rethink. Don't worry, Abap developers will still be needed, because experience shows that about one-third of enhancements continue to happen in core. There just isn't a suitable in-app or side-by-side solution for every requirement yet.

And how do you get started? This question comes up again and again. Maybe you read the SAP blogs about in-app extension and extensibility via the BTP. Or you might check out what's new at Steampunk! The term stands for using Abap in the cloud. Steampunk is a great way to build innovative applications independent of your own SAP on-prem landscape and releases. Let me put it this way: If you are curious and get to grips with the topic early on, you will have a lot of fun in the coming S/4 projects.

Maximilian Krcmar, cbs

Max Krcmar is Manager in the Cloud Platform division at cbs Corporate Business Solutions

Write a comment

Working on the SAP basis is crucial for successful S/4 conversion. 

This gives the Competence Center strategic importance for existing SAP customers. Regardless of the S/4 Hana operating model, topics such as Automation, Monitoring, Security, Application Lifecycle Management and Data Management the basis for S/4 operations.

For the second time, E3 magazine is organizing a summit for the SAP community in Salzburg to provide comprehensive information on all aspects of S/4 Hana groundwork. All information about the event can be found here:

SAP Competence Center Summit 2024


Event Room, FourSide Hotel Salzburg,
At the exhibition center 2,
A-5020 Salzburg

Event date

June 5 and 6, 2024

Regular ticket:

€ 590 excl. VAT


Event Room, Hotel Hilton Heidelberg,
Kurfürstenanlage 1,
69115 Heidelberg

Event date

28 and 29 February 2024


Regular ticket
EUR 590 excl. VAT
The organizer is the E3 magazine of the publishing house AG. The presentations will be accompanied by an exhibition of selected SAP partners. The ticket price includes the attendance of all lectures of the Steampunk and BTP Summit 2024, the visit of the exhibition area, the participation in the evening event as well as the catering during the official program. The lecture program and the list of exhibitors and sponsors (SAP partners) will be published on this website in due time.