S/4HANA & Brownfield - the shortcut that will leave you shortchanged

These choices often reveal underlying conflicts of interest—between short-term gains and long-term value, convenience versus innovation, or even what your service integrator advises on and delivers versus one's real organisational needs. Those companies favouring a more brownfield approach, can also say a lot about the leadership style and mentality, leaning heavily towards pragmatism and risk aversion. So, ask yourself: What kind of organisation are you? One that plays it safe, or one that takes a decisive step into the future? Where relevant, comparisons are mainly drawn between brownfield and greenfield approaches - bear in mind that hybrid or selective data transition (SDT) sits somewhere in between. But the purpose of this article is not to describe the various migration approaches in detail, but to understand the motivations and highlight the risks associated with a precautionary system conversion approach to S/4HANA, and the potential harm it could do to your organisation in the long run. 

 

The Hidden Pitfalls of a Brownfield Migration

The brownfield approach to transitioning to SAP S/4HANA involves upgrading an existing SAP ERP system to the newer S/4 version while maintaining much of the existing data, customisations and configurations. It is often perceived to be a 'safer' choice for organisations seeking to minimise disruption and reduce short-term costs. However, while this approach can offer a smoother initial transition, it inherently carries the risk of amplifying technical debt, a burden of outdated or inefficient systems and processes that hinders an organisation's agility to seize innovation opportunities and adapt to changing market forces and customer demands.

Fig.1 Brownfield: progress or stagnation?

 

Outdated applications 

A key risk of a Brownfield migration is its tendency to perpetuate application landscape obsolescence. By upgrading the ERP system without re-evaluating the broader ecosystem, organisations may retain outdated or redundant applications that hinder S/4HANA’s streamlined capabilities. These legacy tools, often customised for outdated processes, no longer provide the benefits they once did. Organisations lose sight over time as to whether they continue to add value, and in many cases lead to inefficiencies, higher maintenance costs, and limited scalability. To mitigate this, organisations should assess their application landscape during migration planning, identifying redundant or obsolete tools, aligning applications with S/4HANA’s advanced features, and replacing outdated systems with modern, standardised solutions. SAP LeanIX, an industry leading enterprise architecture management platform incorporates advanced application rationalisation features to help organisations ensure their new ERP landscape is efficient, secure, and aligned with future business needs. For more information on SAP LeanIX, see here.

 

Inefficient Processes

A brownfield migration to S/4HANA often perpetuates legacy SAP ECC inefficiencies stemming from decades of accumulated customisations and modifications, and outdated process models. This results in complex and fragmented processes that are challenging to maintain, adhere to and improve. Furthermore, ECC processes frequently operate in silos, with minimal integration between departments or systems, leading to operational inefficiencies and bottlenecks. Many processes persist simply because "that's how it's always been done," but are often plagued by excessive manual interventions and convoluted workflows, which many organisations simply don't have proper visibility of, let alone control over. Tools such as SAP Signavio Process Insights and Process Intelligence provide visibility and transparency of process execution and performance, and pinpoint opportunities for optimisation.

Since brownfield projects often focus on a "lift-and-shift" migration, those companies that adopt such an approach may miss the opportunity to take advantage of the plethora of S/4HANA innovations like embedded analytics, simplified and standardised processes, and industry best practices, not to mention enhanced user experiences through Fiori apps and artificial intelligence.

 

Poor Data Quality & Integrity

Another key challenge of the brownfield approach is that it often retains legacy data, including outdated, redundant, or irrelevant information. When migrating an entire dataset, any errors or inconsistencies in the old system are carried over into the new one. This means that instead of taking full advantage of S/4HANA's advanced capabilities, organisations might find themselves constrained by the same data issues that hindered performance in the old system. 

A further drawback is the limited opportunity for data cleansing. In many cases, the primary goal of a brownfield migration is ensuring that the system transition works seamlessly, which means there is often little focus on cleaning up data beforehand. This oversight can have severe consequences, as poor data quality may lead to inaccurate insights and suboptimal decision-making, reducing the effectiveness of S/4HANA’s embedded analytics and reporting capabilities. 

Moreover, the brownfield approach misses an opportunity for a strategic rethinking of data management. A greenfield migration, which involves building a new system from scratch, allows organisations to clean up unnecessary data, implement modern data governance practices, and ensure compliance with present-day and future regulations such as GDPR and sustainability directives. By sticking with a brownfield approach, organisations risk perpetuating inefficiencies and failing to address compliance challenges.

The impact on system performance is another important consideration. Carrying over large volumes of old and irrelevant data can slow down the new system. SAP S/4HANA is designed for high-speed, in-memory computing, and contaminating it with outdated data can prevent it from operating at its full potential. To mitigate this risk, organisations must consider conducting a thorough data assessment and cleansing before migration to ensure that only high-quality, business relevant data is carried over. SAP Signavio Process Insights already mentioned before, is also really useful for identifying and cleansing old and redundant open documents that contaminate operations and clog up database tables.

Finally, the brownfield approach can delay decisions around data archiving. Without a clear data archiving strategy, the organisation may end up with inflated data volumes, leading to higher storage costs and slower query performance.

Fig. 2 Brownfield v Greenfield migration approach. Or somewhere in-between?

A much favoured approach is adopting a hybrid strategy, where selective data transition (SDT) is used to strike a balance between the continuity offered by brownfield and the fresh start provided by greenfield using a phased approach to migration. But whatever the approach, implementing a robust process and data governance strategy will ensure that only relevant data is transferred, new processes are adopted and followed, supporting long-term performance and compliance.

By addressing these challenges, organisations can take full advantage of S/4HANA’s capabilities without dragging along legacy data and process issues.

To see how you can already start identifying and actioning data cleansing and process improvement opportunities in your current ECC system, why not check out our bite size demo on the power of SAP Signavio Process Insights here.

 

What a Brownfield Approach May Say about Leadership Philosophy

Up til now we have discussed the disadvantages and constraints of adopting a brownfield approach to S/4HANA transitioning. The business case for kicking this approach into touch appears strong from a pure technical, process or data perspective. But what about organisational strategy, culture or change mindset? There are a number of factors which might sway organisations to still opt for a brownfield approach. Let's explore these in detail, weighing them up against a greenfield approach, and see what this may reveal about their leadership. 

Risk-Averse and Change-Resistant                                                                                                Choosing a brownfield approach may reflect a leadership style that prioritises stability over transformation. Leaders who opt for this method might view the potential risks of disruption or organisational resistance as outweighing the benefits of a greenfield or hybrid migration. This suggests a cautious approach to change, with leaders focused on maintaining the status quo rather than pursuing bold transformation.

Focus on Cost Containment
A brownfield migration often indicates that the leadership is looking to contain costs in the short term. Financial conservatism, possibly driven by budget and timeline constraints, may take precedence over long-term investments in innovation. This reflects a mindset that favours operational continuity over rethinking how technology can provide a competitive advantage. Greenfield projects tend to require more investment upfront due to the extensive re-engineering of processes, while brownfield projects can be less costly but may offer less flexibility in terms of redesigning business operations. Moreover, greenfield implementations generally take longer to execute as they involve starting from scratch, which means more time is needed for planning, testing, and user training. A brownfield approach, while potentially faster, could still require significant effort in terms of testing to ensure the system conversion runs smoothly.

Operational Continuity is Paramount
In some cases, leaders choose a brownfield approach because they are deeply focused on minimising disruptions to ongoing business operations. This is often the case in industries where any disruption could have severe consequences, such as manufacturing, healthcare, or utilities. The decision signals a strong commitment to protecting existing customer experiences and revenue streams, even if it means sacrificing transformational change. It reflects an effort to balance the interests of multiple stakeholders, including shareholders, employees, and customers by managing the competing pressures of cost, operational stability, and innovation.

Short-Term Focus or Limited Strategic Vision
Organisations that select a brownfield approach may not have a long-term digital transformation vision. Instead, they might be reacting to immediate pressures, such as the looming end-of-support deadline for their current SAP ERP system, rather than proactively seeking to innovate. This can indicate a reactive approach to change rather than a proactive strategy for long-term transformation.

Constraints on Resources and Skills
Some leaders may recognise that their organisation lacks the internal expertise or resources to handle the complexity of a greenfield migration.  In this case, a brownfield approach may represent a more realistic, achievable path forward, ensuring that the migration can proceed smoothly without overburdening teams.

A Pragmatic or Incremental Change Mindset
For some organisations, a brownfield approach is seen as a manageable first step toward transformation. Rather than pursuing radical transformation all at once, leaders might prefer incremental change, planning to optimise or innovate after the system is stable. This reflects a preference for practicality and a phased approach to transformation (experience suggests however that a brownfield approach can actually hinder an organisation's ability for future incremental change).

Reactive Rather Than Transformative
Organisations that opt for a brownfield approach might do so more out of external pressures than a clear strategic desire to innovate. This suggests that leadership is more focused on responding to immediate challenges, like the need to upgrade an outdated system or the looming end of SAP ECC mainstream maintenance support in 2027, rather than using the migration as a unique opportunity to transform the business.

The sands of time are running low for SAP ECC. So what factors motivate an organisation's migration approach to S/4HANA? The following radar chart reflects the weightiness against a number of factors for each of the various approaches. The closer the resemblance of the plotted outcome to this 'hourglass' figure, the more likely a brownfield approach would be favoured. 

Fig. 3 S/4HANA migration approach motivation factors

Opting for a brownfield approach can indicate that leadership is pragmatic and conservative, prioritising risk management, operational continuity, and cost containment. It may also reflect a reactive, rather than proactive, approach to change, with leaders focused on addressing immediate needs rather than pursuing bold, long-term transformation. While this approach may be well-suited to organisations with limited resources or a preference for incremental change, it would still be difficult to quell negative perceptions about an organisation's lack of long-term vision, whilst also posing the risk of missing the chance for innovation and transformation. With the right approach, strategy, methodology, tools and people, transitioning to S/4HANA is a once-in-a-generation opportunity to truly transform your business.

 

At Rapid X, we not only specialise in helping clients navigate successful S/4HANA transitions, but provide support during the pre-project phase as well, including business case creation, vendor selection, transition planning, and strategic advice on other critical decisions such as migration approach. If you'd like to know more, get in touch with us today.