H4S4 Under Time Pressure

An SAP HR transition is often less about new features and more about how to safely migrate legacy systems, custom rulesets, and established processes to the next generation. This was precisely the challenge Kurtz Ersa faced. The technology group opted for an H4S4 transition using a brownfield approach, relying on an SAP Readiness Check, a clear testing strategy, and a new key-user model.

The project demonstrates why a successful HR transition is much more than just a technical migration—and what insights other companies can draw from it for their own roadmap.

The deadline sets the direction

Not every transformation begins with an innovation strategy. Often, it is a clearly defined deadline that creates the need for action. At Kurtz Ersa, this was an expiring compatibility agreement for the HR solution in use, set to end on December 31, 2025. This made one thing clear: The existing SAP HCM landscape had to be migrated to H4S4 in a timely manner to ensure that operations remained compliant and supportable. At Kurtz Ersa, this is compounded by the fact that payroll and time management are handled centrally for several group companies. Approximately 1,050 payroll units are processed each month. Different collective bargaining agreements, individual company agreements, and various co-determination structures mean that the system landscape goes far beyond standard operations. Every adjustment must function reliably; once payroll is complete, it’s time to prepare for the next cycle.

Kurtz Ersa Opted for Brownfield

Against this backdrop, a conscious decision was made to adopt a brownfield approach. The goal was not to redesign all processes from scratch, but rather to systematically transfer proven workflows, existing regulations, and customizations to the new environment.

„The premise was clear: We wanted to keep what had proven itself,“ says Jürgen Stahl, Team Leader of Business Process Solutions at Kurtz Ersa, describing the starting point. Especially in complex HR systems with numerous collective bargaining and company-specific features, a greenfield approach would have meant additional effort and new risks. However, “brownfield” does not mean simply adopting everything as-is. Rather, it involves critically reviewing existing solutions and ensuring they are technically future-proof. Proven processes should be retained, while at the same time technical dependencies, in-house developments, and new requirements had to be taken into account.

In the HR field in particular, this approach is often the less risky option. The specific provisions of collective bargaining agreements, company agreements, and sets of rules that have evolved over time cannot be easily standardized. The goal, therefore, was not to reinvent existing processes, but rather to transition them in a controlled manner to a future-proof technical environment.

Readiness Check as a Foundation

The SAP Readiness Check played a central role in this process. For Kurtz Ersa, it was far more than just a technical formality. The check analyzed the current state of the system and highlighted the issues that needed to be addressed before the transition. These included in-house developments, coding adjustments, replaced functions, and Fiori-related issues. At the same time, it provided a solid foundation for further project planning.

„Brownfield doesn’t just mean taking everything that’s already there. The key is to know early on which developments and adjustments are still technically viable—and where targeted revisions or replacements are needed,“ explains André Schaupp, Team Manager for Product Design & Customer Development HRM at FIS. The transparency gained helped identify risks early on, prioritize tasks, and make informed decisions. At the same time, the Readiness Check established a shared functional and technical perspective on the project. Instead of identifying individual issues only during implementation, dependencies could be assessed early on and necessary measures planned in a structured manner. This reduced risks and made prioritization easier.

Clean up first, then migrate

A particularly practical lesson from the project emerged even before the actual transition. Kurtz Ersa took the opportunity to critically review its existing HR landscape and streamline it in a targeted manner. Among other things, payroll areas, personnel areas, variants, and wage types that were no longer in use were eliminated. This step was not technically necessary. Nevertheless, it proved useful for reducing the complexity that had built up over time.

Many outdated records that are no longer needed in day-to-day operations—such as those for employees who left the company long ago—have been cleaned up. This makes daily work much more organized. As is often the case with HR systems that have evolved over time, structures had accumulated over the years that no longer provided any operational value. The transition provided the perfect opportunity to clean up this legacy baggage and reduce future complexity. Those who take advantage of this moment will not only start with a new technical foundation but also with a significantly leaner and more streamlined system landscape.

Especially in areas such as payroll and time tracking, this has a positive long-term impact on maintenance, testing, and day-to-day work.

„The greatest success is actually that we have the key users
brought on board. That has helped the collaboration
between the department, IT, and the project team, a
”given a new impetus."

Jürgen Stahl,
Team Leader, Business Process Solutions,
Kurtz Ersa

Key User as a Success Factor

Although the technical migration was successful, those involved see the greatest benefits elsewhere. As part of the project, dedicated key user structures were established for the first time for payroll and time management. Two key users in each area took on the role of business coordination, consolidated questions, oversaw testing, and served as central points of contact between the business unit, IT, and the project team. „The greatest success is actually that we got the key users on board. This has given new momentum to the collaboration between the business unit, IT, and the project team,“ summarizes Jürgen Stahl.

The key users ensured that business requirements were consolidated, impacts were assessed early on, and decisions could be prepared on a sound basis. This exchange proved particularly valuable in time management. In addition, the key users became advocates within the company. They consolidated knowledge, structured communication, and helped address requirements more quickly and effectively.

At the same time, critical expertise was no longer tied to individual employees but was more broadly embedded throughout the company. Successful H4S4 transitions are not determined by technology alone, but also by clear lines of responsibility and the involvement of the business units.

Fiori with a Sense of Proportion

Kurtz Ersa also took a pragmatic approach to SAP Fiori. The project’s goal was not to completely replace the SAP GUI. Instead, Fiori was deployed specifically in areas where it would generate immediate added value for employees and managers. These include, in particular, Employee Self Services and Manager Self Services for leave requests, time sheets, pay stubs, and approval processes. For Kurtz Ersa, the priority was not to quickly replace the SAP GUI.

The key was to implement new features where they would provide concrete benefits while keeping existing processes stable. Starting with ESS and MSS proved to be a practical approach. At the same time, the project demonstrates that the introduction of Fiori is much more than just a change in the user interface. Roles, authorizations, and processes must be considered together so that users can truly benefit.

What Remains After the Go-Live

The H4S4 transition at Kurtz Ersa shows that successful HR transformations do not depend solely on the technical go-live—they are much more than just technical migration projects.

The key to success was the combination of a clear project structure, early involvement of specialized departments, a robust key-user model, and collaborative implementation with the service provider and SAP Gold Partner FIS. The FIS/hrd CCC copy and comparison tool and the FIS/hrd Schema and Rules Analyzer (SRA) were also used to support the process.

They helped conduct realistic tests, review complex sets of rules in a transparent manner, and ensure the smooth operation of payroll and time management even during ongoing H4S4 operations. This not only successfully implemented a necessary transition but also laid a solid foundation for the further development of the HR system landscape.

Click here to read the full success story: https://www.fis-gmbh.de/de/success-stories/kurtz-holding-gmbh-und-co-beteiligungs-kg/

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