SAP ECC 2027: What Companies Can Still Realistically Achieve in 2026

The end of SAP ECC is not a new topic. But for many companies, it is becoming increasingly concrete. SAP provides mainstream maintenance for the core applications of SAP Business Suite 7 until the end of 2027. After that, optional extended maintenance is available until the end of 2030.

For companies still running SAP ECC, this means one thing: the time for broad strategic discussions is getting shorter. 2026 is no longer the year to simply keep the topic on the agenda. It is the year to make well-founded decisions.

What target architecture is realistic? Which migration strategy fits the business? How much custom code needs to be adapted? Which processes should be kept, harmonized, or redesigned? And how can the existing SAP landscape remain stable while the transformation is underway?

These are the questions that determine whether the move to SAP S/4HANA remains manageable or turns into a reactive large-scale project.

Why 2026 Is a Critical Year for SAP ECC Customers

Many companies underestimate how much preparation is required before an S/4HANA migration can begin. The technical conversion itself is only one part of the overall project. Before that, systems need to be assessed, dependencies reviewed, data quality checked, custom developments analyzed, and target processes defined.

At the same time, pressure increases as the maintenance deadline moves closer. Internal IT teams, business departments, and external consulting resources will all become more constrained. Companies that start too late have less flexibility around timeline, budget, resources, and migration approach.

An S/4HANA transformation therefore requires more than technical execution. It requires a clear roadmap.

What Options Companies Have Now

Companies still using SAP ECC generally have several possible paths. The right option depends on the system landscape, process maturity, data quality, custom code, and overall business strategy.

1. Brownfield: Converting the Existing System

With a brownfield approach, the existing ECC system is technically converted to SAP S/4HANA. This can be a suitable path when processes are largely stable and the company wants to retain much of its existing structure.

The advantage: companies do not have to start from scratch. The disadvantage: existing complexity, historically grown processes, and technical debt can be carried into the new system if they are not properly assessed beforehand.

2. Greenfield: Starting Fresh

With a greenfield approach, SAP S/4HANA is implemented as a new system. This creates the opportunity to align processes more closely with the standard and deliberately leave old complexity behind.

The advantage: more room for standardization and modernization. The disadvantage: the organizational effort is higher because processes, data, and structures need to be newly designed or significantly changed.

3. Selective Data Transition: Taking a Targeted Approach

Selective Data Transition sits between brownfield and greenfield. Companies can transfer selected data, processes, or organizational units and decide more precisely what should be retained and what should be rebuilt.

This approach is particularly relevant for companies with complex system landscapes, international structures, or a desire not to move the entire historical data set into the new system.

Custom Code Often Becomes the Critical Factor

Custom code is one of the most important aspects of an SAP ECC to S/4HANA migration. Many ECC systems have grown over years or even decades. Custom developments, modifications, reports, and individual enhancements are often deeply embedded in business processes.

Before a migration, companies need clarity on key questions:

• Which custom developments are still being used?
• Which ones are business-critical?
• Which ones can be replaced or retired?
• Which ones need to be adapted for SAP S/4HANA?
• Which adaptations can be automated or prepared in advance?

SAP recommends using tools such as the ABAP Test Cockpit with SAP S/4HANA checks for custom code migration. These checks help identify relevant findings related to S/4HANA simplifications and point to SAP Notes for resolution.

But the analysis alone does not solve the issue. It shows where action is required. The actual adaptation work remains a separate project workstream that should be planned early.

What Companies Can Still Realistically Achieve in 2026

Not every company will be able to complete a full S/4HANA migration in 2026. But almost every company can create the foundation for a controlled transformation.

The most realistic and valuable steps include:

1. Conduct a Readiness Assessment

A readiness assessment creates transparency around system status, data, custom code, add-ons, interfaces, and technical prerequisites. It is the foundation for a reliable roadmap.

2. Decide on the Migration Strategy

Greenfield, brownfield, or Selective Data Transition should not be chosen based on instinct. The decision needs to fit the IT landscape, process reality, and business strategy.

3. Analyze and Prioritize Custom Code

Not every custom development needs to be carried forward. A structured custom code assessment helps reduce effort and identify critical adaptations early.

4. Define the Target Architecture

SAP S/4HANA is not just a new ERP system. For many companies, it is the entry point into a more modern architecture with SAP BTP, stronger integration, improved data foundations, and new extension possibilities.

5. Connect Transformation and Operations

Many companies need to keep their existing SAP systems stable while preparing or executing the migration. AMS, Basis Services, monitoring, and project delivery should therefore not be treated as separate topics.

Why Waiting Increases Risk

A late start may seem convenient in the short term. In the long term, it increases risk. The less time remains, the more decisions are shaped by pressure rather than strategy.

This can lead companies to:

• choose the wrong migration approach,
• analyze custom code too late,
• involve business departments too little,
• underestimate data quality,
• increase transition costs,
• or carry technical debt into the new landscape.

Starting early does not necessarily mean beginning the full migration immediately. It means creating clarity and planning the next steps based on facts.

How Lupus Consulting Can Support

Lupus Consulting helps companies plan the move from SAP ECC to SAP S/4HANA in a structured, realistic, and executable way. This includes strategic consulting, technical analysis, Custom Code Adaptation, SAP Development, SAP Basis Services, and Application Management Services.

Especially in complex system landscapes, it is important not to look at the migration in isolation. The decisive factor is the interaction between target architecture, code adaptation, operations, process understanding, and long-term maintainability.

With the Lupus Consulting CCA Toolset, a large share of recurring custom code adaptation tasks can be handled more efficiently. This turns a difficult-to-estimate manual workload into a more structured and predictable project component.

Conclusion: 2026 Is the Year to Create Clarity

The SAP ECC maintenance deadline is no longer an abstract date. For many companies, 2026 is the year to turn open questions into a concrete roadmap.

Companies that analyze, prioritize, and decide now gain room to act. Companies that wait risk more pressure, higher complexity, and less control.

The move to SAP S/4HANA is not only a technical migration. It is an opportunity to make the SAP landscape more stable, modern, and future-ready.