How to Make Custom Code Adaptation to S/4HANA More Efficient and Reliable

SAP ECC is retiring. As powerful as it has been, SAP S/4HANA is ready to take its place. However, S/4HANA is not an upgrade — it is an entirely new platform that runs on the HANA in-memory database rather than traditional data center architecture. And while this new ERP system makes everything faster, leaner, and more efficient, the transition introduces several major challenges, one of the biggest being Custom Code Adaptation.

Why Custom Code Adaptation?

SAP ECC has been in use for over 20 years and has covered countless customer-specific requirements — but not all of them. That is where individual custom code comes into play. As useful as these tailored solutions are, they now pose a challenge when moving to S/4HANA.
SAP will discontinue support for ECC in 2027, meaning migration is inevitable and will have to happen sooner or later.

Custom Code Check: ABAP Test Cockpit (ATC)

Thorough preparation is essential for a successful migration and begins with understanding the project’s scope and complexity. SAP provides a free tool for this purpose: the ABAP Test Cockpit (ATC).

ATC is extremely valuable for S/4HANA migrations. It identifies which parts of the existing ECC custom code are incompatible with the simplified S/4HANA data model. It highlights syntax changes, removed or modified transactions, and database dependencies that no longer exist in S/4HANA. ATC also supports remote code analysis, enabling S/4HANA-specific checks to be performed directly on the ECC system, without having to move any code.

This early insight significantly reduces risks and effort. Teams know exactly which objects must be adapted, can prioritize development tasks, estimate workloads more accurately, and avoid unpleasant surprises. Combined with exception management and detailed reports, ATC creates the foundation for a structured, transparent, and seamless custom code adaptation process.

What Comes Next?

Obstacles in the Migration

Once an organization understands the scope of its migration and the amount of custom code involved, the main obstacles often shift from strategy to execution and implementation.

Knowing the project size simplifies workload estimation, but the work itself remains the same: diagnostics can be automated, yet the actual code adaptation still requires manual intervention. Developers must review each case individually and adjust the code accordingly.

Custom Code Adaptation During S/4HANA Migration

One of the most time-consuming tasks during migration is adapting custom code to new data structures and processes. Many of these changes must be implemented manually to ensure smooth system functionality after migration.

Typical Examples of Custom Code Adaptations

• Material Number Length: In ECC, material numbers are limited to 18 characters. S/4HANA allows or even requires up to 40 characters. All programs, reports, and interfaces that handle material data must be reviewed and adjusted accordingly.
• Call Transactions and Batch Inputs: Call transactions and batch inputs operate on the principle of recording classic GUI transactions and replaying them automatically. However, S/4HANA no longer uses the traditional SAP GUI since its interface is browser-based. Therefore, these methods can no longer be used. They are replaced by BAPIs (Business Application Programming Interfaces), which trigger processes in a clean and future-proof manner.
• Outdated Transactions:Many older transactions rely on deprecated calling conventions or direct table access. In SAP ECC, numerous standard function modules existed for this purpose — some of which are now obsolete and have been completely removed in S/4HANA. Custom transactions that still rely on such modules or access tables like MARA or MAST directly must be reworked. Instead, they should use the modern interfaces available in S/4HANA, such as APIs or BAPIs, to ensure long-term stability and compatibility.
• Business Partner Conversion: A central element of custom code adaptation is the transition to the Business Partner model. In SAP S/4HANA, customer and vendor data are no longer stored in the traditional tables (e.g., KN*, LF*). Custom programs that previously accessed these tables directly must now be adapted to the new Business Partner concept. Only then can smooth data handling be ensured within the S/4HANA environment.
• Output Management and User Interfaces: Many custom output programs in ECC rely on SAPscript or SmartForms. In S/4HANA, these technologies behave differently. Adjustments or complete redevelopment are often required to meet new output standards. In most cases, a reorganization using Adobe Forms is also possible.

The spectrum ranges from material numbers and interfaces to output processes. For smaller companies, this can involve hundreds to thousands of changes; for large corporations, even millions. Automation and efficient workflows are therefore critical to a successful migration.

CCA Toolset: AI-Supported Assistance During Migration

What Is the CCA Toolset?

The CCA Toolset is an AI-based application that processes the checklist generated by ATC and independently carries out code adaptations. While most adjustments are simple, they are often highly time-consuming exactly the type of work the Toolset performs automatically, and in just minutes.

What Tasks Does the CCA Toolset Perform?

The CCA Toolset can handle around 80% of all migration-related adaptation tasks. These include modifications to extended data fields (e.g., material number length from 18 to 40 characters), changes due to HANA database specifics (e.g., adjustments to SELECT statements), or the replacement of obsolete functions with S/4HANA-compliant equivalents.

How Much Time Can Be Saved?

Using the CCA Toolset can reduce migration time by 30–40%. Moreover, the tool can forecast the total time required for migration with an error margin of just 5%, a significant advantage for both scheduling and budgeting.

What Makes the CCA Toolset Unique?

It can be used in two different scenarios:

1. Standard Migration:
   The entire system is migrated to S/4HANA. The Toolset is installed after migration, and the custom code adaptation is performed there.
2. Pre-Migration:
   The Toolset is installed on ECC before migration, downloads data points and custom code, performs the necessary adaptations, and writes them back into ECC. When the migration to S/4HANA takes place, many adaptations are already complete.
   (Note: Not all objects can be adapted while still on ECC. Objects that are directly S/4HANA-related, such as Business Partner–dependent adaptations can only be processed after migration.)

Can I Use the Toolset Without AI?

Yes. Even though our solution adheres to the highest security standards and no data ever leaves the system, we understand that some organizations prohibit the use of AI. The Toolset can also run without the AI component. While this reduces part of its added value, even the non-AI version still shortens migration time significantly.

How Can I Access the CCA Toolset?

The CCA Toolset is an add-on developed by Lupus Consulting. Schedule a consultation to learn how it can support your S/4HANA migration and accelerate your custom code adaptation.