With the end of mainstream maintenance for SAP ECC looming in December 2027, organizations worldwide are faced with the critical task of planning their S/4HANA journey. While the benefits of moving to SAP's next-generation ERP system are undeniable, the path to get there isn't always clear. Should you convert your existing ECC environment, start fresh with a new implementation, or consider a hybrid approach?

Many organizations view their S/4HANA transition as more than just a technical upgrade; it's an opportunity for business transformation. This blog will focus on the brownfield conversion approach and outline key considerations to help you get started.

1. Evaluating Your Current Environment

Before making any major decisions, organizations should conduct a comprehensive assessment of their current ECC system. Luckily, SAP provides free tools that can help in this evaluation:

• SAP Readiness Check – Assesses compatibility with S/4HANA, identifying potential challenges.

• SAP Signavio Process Insights – Provides insight into existing processes and areas for improvement.

These tools will help you understand your current landscape and determine whether a brownfield conversion is the right path for your organization.

2. Preparing for the Conversion

If you choose to convert your existing ECC environment, there are key preparatory steps that can be taken now to minimize risks and streamline the transition:

• Run the Simplification Checkto identify changes required for S/4HANA compatibility.

• Convert Classic GL to New GL to align with the S/4HANA financial structure (if needed).

• Implement Customer/Vendor Integration (CVI) to harmonize master data.

• Perform ABAP Test Cockpit (ATC) scans to S4 impacts to custom code.

By proactively addressing these areas, your organization will reduce complexity when embarking on the full S/4HANA project.

3. Managing Interfaces and Integration

Interfaces play a crucial role in any ERP system, so it's essential to compile a list of existing integrations and determine which ones need replacement or enhancement. Organizations may consider SAP BTP Integration Suite to streamline connectivity between SAP and non-SAP systems.

4. Developing a Comprehensive Test Strategy

A robust test plan ensures a smooth transition to S/4HANA. Start by compiling a list of test case scenarios, covering:

• Standard and custom processes

• Critical integrations

• End-user roles and authorizations

Investing in thorough testing mitigates go-live risks and ensures system stability.

5. Defining Your Fiori Strategy

One of the major changes in S/4HANA is the shift toward SAP Fiori for a modern user experience. Organizations must decide whether to deploy Fiori during the conversion project or go live with SAP GUI first, then implement Fiori later. Balancing project scope and user readiness will be key factors in this decision.

6. Building Your Project Roadmap

A well-defined project roadmap ensures alignment with business goals. Consider whether a single-phase go-live is realistic, or if a multi-phase approach (such as a 1-year, 3-year, and 5-year roadmap) is more suitable. The roadmap should be carefully structured, balancing technical conversion, process enhancements, and business transformation over time.

7. Understanding SAP’s Cloud Strategy

SAP is heavily investing in cloud innovations, so organizations must evaluate their S/4HANA Private Cloud offerings and prioritize which products to implement in the first few years vs. those that can be added later. While cloud adoption unlocks future innovations, businesses must remain realistic about when new technologies (like AI-powered capabilities) will be available for use. Ensuring a stable foundation before adopting cutting-edge tools is crucial for long-term success.

8. Getting Expert Guidance

Transitioning to S/4HANA is a complex process that requires careful planning and execution. Partnering with CONTAX for expert guidance will help ensure a successful implementation, leveraging best practices and industry insights.

Final Thoughts

Starting your S/4HANA journey may feel overwhelming, but by leveraging free evaluation tools, preparing key components in advance, defining a realistic roadmap, and seeking expert support, you can navigate the transition with confidence. Whether you're looking for technical conversion or long-term process improvements, proper planning will be the cornerstone of a successful S/4HANA transformation.