Unlocking the Power of Clean Core: A Practical Approach to Modernizing Legacy SAP Systems

Clean Core Strategy is a practical approach to manage 30 years of SAP custom development, aiming to get back control over custom developments and address technical debt. The company migrated to S/4 HANA but kept most custom code due to time and budget constraints. The strategy focuses on innovating and renovating the system, recognizing it as a marathon rather than a sprint race. The blog series aims to provide arguments for the board and team to invest in Clean Core and assist in defining a strategy and tasks.

The Clean Core strategy is a practical approach aimed at managing 30 years of SAP custom development, focusing on regaining control over custom developments and addressing technical debt. The company has migrated to S/4 HANA but has retained most of the custom code due to time and budget constraints. This strategy emphasizes innovation and renovation, recognizing the process as a marathon rather than a sprint.

Background
The Clean Core strategy was developed in response to the need to reduce technical debts and ensure the core system remains clean and compliant with new developments. The initiative began with a clear understanding that the current system was heavily modified, leading to difficulties in maintenance and future development. The strategy involves several key components: measurement and scoping, creating awareness, defining guidelines and governance, implementing quality gates, and engaging the team.

Measurement and Scoping
Before initiating the cleanup, it is crucial to assess the current state of the system. This involves identifying all custom code objects, modified objects, user-exits, BAdIs, custom reports, and print forms. The Clean Core Index, a new KPI, measures the system's cleanliness, with a lower value indicating better compliance. The company has developed CDS views to track progress and utilizes SAP standard technologies for Custom Code Lifecycle Management.

Creating Awareness
Explanation of the importance of Clean Core to the Board of Management and business departments is essential. The initial investment in Clean Core activities may not yield immediate business benefits, but it is crucial to communicate the long-term advantages, such as reduced maintenance costs and increased system stability. Training materials have been created to educate colleagues about the benefits and importance of Clean Core.

Development Guidelines and Governance
The strategy includes defining development guidelines that cover the rules for developing in SAP, including the use of S/4 development objects and paradigms. A strong governance process is implemented to ensure informed decisions and prevent unauthorized modifications. Quality gates, such as the ABAP Test Cockpit (ATC) checks, are mandatory before deploying code into productive environments.

Engagement and Learning
The company has created a learning journey for each team member, encouraging them to explore and get familiar with S/4 development principles. They have introduced a communication channel in MS Teams to share knowledge and experiences. Additionally, each team member investigates SAP BTP solutions to identify potential use cases and benefits.

Targets and Timeline
Clean Core is a long-term project, with short-term targets such as preventing modifications and activating mandatory ATC checks. Mid-term targets include making ABAP code-PAL mandatory and stopping the development of custom reports. Long-term targets involve evaluating tier-3 enhancements and migrating user-exits into BAdIs. Progress is measured quarterly and shared with the entire IT team and management.

Conclusion
The Clean Core strategy is a comprehensive approach to managing SAP custom development and addressing technical debt. By focusing on measurement, awareness, guidelines, governance, engagement, and targets, the company aims to innovate and renovate the system, ensuring long-term stability and reduced maintenance costs.

References
[1] https://community.sap.com/t5/technology-blog-posts-by-members/clean-core-strategy-a-practical-approach-to-get-a-cleaner-on-premise-system/ba-p/14180323