Project roadmap from ECC to S/4 HANA

In this blog post, I want to show how to build a project roadmap from ECC to S/4 HANA conversions. ECC to S/4 HANA conversions are long running projects, which can multiple years, and can have serious impacts when something goes wrong. Having the right project roadmap is therefore essential to complete these conversions successfully.

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In your project roadmap you need to consider the following steps:

1. Selecting to S/4 HANA edition suitable for your business
2. License purchasing
3. Identify business processes which should be implemented with S/4 HANA
4. Identify unused or obsolete custom code, printed forms or master data like materials, business partners, company codes or sales organizations.
5. Selecting the right migration strategy
6. Prepare the infrastructure
7. Run HANA readiness checks and prepare custom code for S/4 HANA in ECC
8. Setting up development, test and productive S/4 HANA instances
9. Prepare and execute migrations in the test instances
10. Validate the test migrations
11. Create Go-Live scenarios
12. Go-Live with hypercare phase

Selecting to S/4 HANA edition suitable for your business

Your first critical step is to select the most appropriate S/4 HANA edition by evaluating the options against your business needs. If you missed it, our last blog post explained the features and distinctions of the different S/4 HANA editions.

License purchasing

The license topic is more complex than you may think. First S/4 HANA sorts users into different groups based on their permissions:

• Professional users
• Functional users
• Productivity users

For each group you need a separate license with a unique license fee. Professional users have currently the highest fees and productivity users the lowest fees. To buy these licenses you need to contact your SAP partner and send him how many users belong to the different user groups. SAP provides a report in transaction code SLIM_UCH for this purpose. Before you send this report to your SAP partner, it makes sense to remove unnecessary or unused permissions, which cause overclassification.

At last, you should not forget to purchase licenses for the operating system, if you want to run your S/4 HANA On-Premises. As S/4 HANA On-Premises currently runs only on SUSE Enterprise Linux or RedHat Linux you will need a license from one of these companies. You can’t simply run the S/4 HANA On-Premises edition on a Microsoft Windows Server or on an Ubuntu Linux server.

Identify business processes which should be implemented with S/4 HANA

The move to S/4HANA is not just a technical upgrade; it’s a business transformation. This phase is crucial for determining how your company will leverage the new features and simplified data model.

• Fit-to-Standard Analysis: Review your existing ECC business processes and map them against the SAP S/4HANA best practices (known as Simplification Items).
• Process Harmonization: Identify opportunities to simplify, standardize, or eliminate custom developments by adopting standard S/4HANA functionality, such as the Universal Journal (ACDOCA) in Finance.
• Scope Definition: Decide which business functions will be migrated with minimal change (often the case in a Brownfield conversion) and which will be fully re-engineered to leverage new S/4HANA capabilities (more common in a Greenfield implementation or Selective Data Transition).

Identify unused or obsolete custom code, printed forms or master data

Your ECC system likely contains years of custom code, reports, and old data. A ‘clean-up’ is essential to reduce the conversion effort and costs.

• Custom Code Analysis: Use SAP tools like the Custom Code Management in SAP Solution Manager or the ABAP Test Cockpit (ATC) to analyze custom code usage. Retire or remove code that hasn’t been used in years.
• Simplification Item Check: The SAP Readiness Check tool will identify custom code that refers to data structures or transactions that no longer exist in S/4HANA. This code needs to be adapted.
• Master Data Cleansing: S/4HANA mandates changes like the Business Partner concept (replacing individual Customer and Vendor masters) and simplified material numbers. Clean up and de-duplicate old master data to ensure a smooth transition and avoid migrating ‘junk’ data.

Selecting the right migration strategy

This is one of the most significant decisions impacting the project’s timeline, budget, and risk profile.

• Brownfield (System Conversion): A technical in-place conversion/upgrade of your existing ECC system to S/4HANA. You keep your existing configuration, custom code (with necessary adaptation), and historical data.
  • Pros: Fastest path, lower business disruption, preserves historical data.
  • Cons: Carries over existing process inefficiencies and old custom code; limits adoption of some S/4HANA innovations.
• Greenfield (New Implementation): A fresh installation of S/4HANA, starting with new configurations and only migrating necessary master and open transaction data.
  • Pros: Clean slate for process re-engineering, full adoption of S/4HANA innovations and best practices.
  • Cons: Most time-consuming and expensive, requires significant effort in new configuration, no automatic transfer of historical documents.
• Selective Data Transition (Bluefield): A hybrid approach where you can consolidate multiple ECC systems, select specific data (e.g., only the last 5 years of financial data), or redesign certain business processes before conversion.
  • Pros: Combines the best of both worlds—selective process re-design while maintaining essential historical data.
  • Cons: Requires specialized tools and expertise, typically more complex than a pure Brownfield approach.

Prepare the infrastructure

S/4HANA runs exclusively on the SAP HANA database. This step involves procuring and setting up the hardware and operating system.

• Sizing: Use the SAP Quick Sizer or the SAP Readiness Check to accurately determine the required hardware resources (CPU, RAM, and storage) for the HANA database and application servers.
• Hardware Procurement: Purchase and install the servers according to the sizing requirements, ensuring they are certified for the HANA database.
• OS Installation: Install the required operating system (SUSE Enterprise Linux or RedHat Linux) and perform necessary configurations as specified by SAP.
• Backup: Make sure to integrate the SAP HANA databases into your backup system. Then you are prepared for emergency cases.

Run HANA readiness checks and prepare custom code for S/4 HANA in ECC

While the infrastructure is being prepared, you can start the technical preparation work in your current ECC system.

• Run SAP Readiness Check: Execute this tool to get a comprehensive report on the required changes, including Simplification Items, custom code impact, add-ons compatibility, and suggested sizing.
• Custom Code Remediation (in ECC): Use the ABAP Test Cockpit (ATC) to analyze and modify custom code in the ECC system to make it compatible with S/4HANA. This is typically done in a separate custom code remediation system (sandbox).
• Implement Prerequisites: Apply necessary SAP Notes and perform mandatory upgrades (e.g., to the highest ECC enhancement package and latest kernel) to meet the minimum requirements for the conversion.

Setting up development, test and productive S/4 HANA instances

This involves establishing the new S/4HANA landscape where the actual conversion and testing will occur.

• Landscape Design: Define the target system landscape (e.g., Development, Quality Assurance, Pre-Production, Production).
• Installation: Install the S/4HANA software on the new HANA-enabled servers for the Development and Quality Assurance systems.
• Configuration: Configure the base settings and perform an initial technical conversion on the Development system, including setting up the new Fiori Launchpad and integrating the Business Partner master data.

Prepare and execute migrations in the test instances

This is the core realization phase, where the transformation plan is put into practice.

• Sandbox Conversion: Perform an initial, full-scale conversion on a sandbox or copy of the ECC system. This provides a realistic test of the process, timing, and identifies unforeseen issues.
• Iteration and Refinement: Repeat the conversion process on the Quality Assurance (QA) system multiple times. Each iteration is a chance to refine the technical conversion steps, remediate custom code, and resolve any functional errors.
• Unit and Integration Testing: After each conversion run on the QA system, execute detailed Unit Tests and Integration Tests to ensure all standard and customized business processes function correctly in the new S/4HANA environment.

Validate the test migrations

Testing and validation are paramount in a long-running conversion project to ensure business continuity.

• Business User Acceptance Testing (UAT): Involve key business users to test their end-to-end processes in the QA system. They should validate that the system meets business requirements and that data migration was successful.
• Performance Testing: Check system performance and response times, especially for high-volume transactions, on the new HANA database.
• Cutover Simulation: Conduct a detailed Cutover Rehearsal on the pre-production system. This simulates the entire production Go-Live process, including downtime estimation, data transfer, and final checks, identifying and resolving any last-minute bottlenecks.

Create Go-Live scenarios

The Go-Live plan is a high-stakes, hour-by-hour script to minimize business disruption.

• Detailed Cutover Plan: Create a highly detailed, time-bound plan of all activities that must occur during the downtime window, including technical steps, validation steps, and fall-back (rollback) procedures.
• Communication Plan: Establish clear communication channels and status update points for the executive team, business users, and technical teams.
• Support Model: Define the Hypercare phase support structure, including team roles, incident management processes, and escalation paths.

Go-Live with hypercare phase

The final step is the execution of the plan and the subsequent stabilization.

• Go-Live Execution: Execute the cutover plan, bringing the ECC system offline, performing the final data loads/conversions, and bringing the new S/4HANA production system online.
• Business Sign-Off: Once the system is live and validated, obtain the formal business sign-off.
• Hypercare Support: The first few weeks post-Go-Live are the Hypercare phase. A dedicated, cross-functional team (Functional, Technical, Basis, and Key Users) provides immediate support to resolve any incidents that arise, ensuring system stability and user adoption.

Conclusion

ECC to S/4 HANA conversions are difficult to master. It makes totally sense to look for external consultants like TechHawks, which can guide you through this difficult terrain.

Want to know more? Register for our free webinar now!