A smarter path to SAP S/4HANA: Brownfield+ transformation for central government authorities

Central government authorities face a unique set of challenges when it comes to modernising their ERP systems. Legacy SAP ECC environments, with layers of customisations built up over years to meet specific needs, are both critical to daily operations and notoriously complex to migrate. With the deadline for standard SAP ECC support approaching in 2027, the move to SAP S/4HANA is now an urgent priority—but that doesn’t mean it has to disrupt the core operations these systems underpin.

This is where a Brownfield+ approach, or Selective Transformation, comes into play. By blending the stability of a traditional Brownfield migration with the opportunity to adopt selected modern Cloud-based ERP capabilities & innovations, this path provides central government authorities with a cost-effective, efficient and practical way forward.

Navigating the complexity of central government systems

For central government authorities, ERP systems do more than execute processes—they are the backbone of everything from budgeting and procurement to compliance and tax administration. However, modernisation possibilities for these systems are often prohibited by:

● Deep customisations tailored to meet highly specific operational and regulatory needs, making migrations complex and resource-intensive.

● Budget constraints that limit the ability to completely overhaul legacy systems in one go.

● Risk aversion within organisations reliant on these systems to deliver public services without interruption.

The way forward: A migration approach that seamlessly combines modernisation with continuity is essential.

Why Brownfield+ is the perfect fit for central government

Here’s how it addresses the specific challenges of central government authorities

• Cost-effective transformation

Unlike a full-scale Greenfield re-implementation, which requires starting from scratch, Brownfield+ retains much of the existing system structure. This significantly reduces costs and project timelines, making it a more budget-friendly option for government entities operating under fiscal constraints.

• Selective innovation

Brownfield+ enables authorities to modernise selectively, unlocking critical features of SAP S/4HANA while leaving non-essential customisations intact. For example, central governments can adopt real-time data analytics, streamlined workflows or advanced automation tools while preserving legacy processes that remain fit for purpose.

• Minimised disruption

With Brownfield+, there’s no need for a holistic overhaul in one go. Instead, the migration can be adapted and tailored to reduce downtime and mitigate risk, ensuring that critical public services remain uninterrupted throughout the transition. There are a significant number of tools to ensure near zero downtime (NZDT) as well as to diagnose and evaluate how the selective transformation is being adopted in reality, and these are covered below.

How Deloitte is supporting central governments through the journey

By combining proven methodologies with a deep understanding of public sector complexities, we provide comprehensive support throughout the process.

We begin by working closely with stakeholders to map out existing systems, prioritise objectives and develop a realistic roadmap that aligns with budgetary constraints and operational needs. This ensures a clear and effective foundation for the transformation ahead.
 

Our tailored Phase Zero approach focuses on modernising where it matters most, leveraging data-driven insights to identify opportunities that deliver value while preserving the aspects of existing systems that continue to perform well. This method avoids unnecessary reinvention, making the transformation both practical and impactful. For central government customers, we will specifically utilize the parts of the model that identify the unique and law-based features essential for the new solution and the areas where significant gains and innovation can be achieved by renewing and optimizing through the migration to S/4HANA. This ensures that law-based functionality is preserved while simultaneously promoting renewal, optimization, and automation during the transition to S/4HANA.

In the Brownfield+ model, we employ SAP-certified tools to ensure a seamless, efficient transition. For example, tools from leading selective data / code software and service providers like smartShift and SNP play a critical role in the selective migration process, automating the analysis and remediation of code and handling complex data migrations with precision. These tools enable us to analyze the existing ECC solution, identifying both challenges and opportunities for optimisation, ensuring a well-rounded and effective transition.

To further enhance process optimisation and uncover re-imagination opportunities, we rely on SAP Signavio’s toolbox for process mining and workflow improvement. By using data insights to assess configurations, automation opportunities, and working routines, we enable organisations to achieve a 360° view of their operations. This approach ensures that every step of the transformation is informed by a deep understanding of the existing systems and guided by the most advanced tools available.

By combining these data-driven technologies with Deloitte’s proven expertise, we ensure that the Brownfield+ approach not only modernises systems but also positions organisations to unlock the full potential of SAP S/4HANA.

Finally, we leverage advanced capabilities through tools like SAP’s Business Technology Platform (BTP) to extend functionality and ensure that we follow SAP's concepts for "Clean Core" in the new S/4 solution. The use of the SAP BTP platform enables governments to adopt cutting-edge features such as predictive analytics, artificial intelligence, and enhanced user experiences, unlocking the full potential of SAP S/4HANA while maintaining operational stability.

A practical path forward

For central government authorities, transitioning to SAP S/4HANA doesn’t mean starting from scratch. With the Brownfield+ approach, organisations can modernise selectively, balancing innovation with continuity while respecting the complexity of their existing systems.

This strategy has already proven its value. For one central government agency, a Brownfield+ migration brought immediate improvements in efficiency and transparency. By integrating real-time analytics, automating workflows and preserving essential legacy processes, they were able to unlock the benefits of modern ERP without the disruption of a full-scale re-implementation.

Deloitte’s deep experience in public sector ERP transformations ensures that every step of the journey is tailored, cost-effective and efficient. By choosing Brownfield+, central governments can embrace the power of SAP S/4HANA on their own terms. Together, we’ll make this migration more than just a change—it will be a transformation.