14    Selecting Your Migration Scenario

To successfully migrate to SAP S/4HANA, the strategy you follow is a decisive factor. This chapter provides support for deciding among the individual SAP S/4HANA migration scenarios.

This final chapter summarizes and compares the advantages and disadvantages of the individual scenarios to provide decision-making support. However, we must mention that we can’t decide for you which scenario you should use. Every customer situation is specific, and consequently, numerous factors play a role when making the decision. In general, the three doors to SAP S/4HANA are always open for all customers if an SAP ERP system already exists. Therefore, careful planning and analysis of your current situation are essential.

The most critical decision is the decision of whether to implement a new system or to convert your existing system. A landscape transformation is a special case because it can be combined with both scenarios. However, you should choose the most economically sensible scenario for your enterprise, and your decision should be based on technical requirements.

The first section starts with a summary of the different options provided by SAP for migrating to SAP S/4HANA. Then, we’ll go into more detail through examples and expectations about possible target landscapes.

14.1    Overview of Procedures and Input Helps

Let’s start with an overall overview, as shown in Figure 14.1. An essential criterion for deciding among the scenarios is your initial situation. Does your source system run SAP ERP 6.0 (or higher), or do you have a different system?

If your SAP system is not supported or if you are using a non-SAP system, you will have to implement a new system. Depending on the volume and quality of your (master) data to be transferred, in a new implementation, you would use the SAP S/4HANA migration cockpit for standard cases or use SAP Data Services for complex data transfers.

Figure 14.1    Decision Tree for the Different Migration Scenarios to SAP S/4HANA

Only for source systems with SAP ERP 6.0 or higher are all three migration scenarios possible. However, you should always consider the following criteria when analyzing your initial situation at an early stage:

• What are the results of the prechecks provided by SAP?
• How much would adapting your custom programs cost, according to the recommendations of the custom code analysis?
• Analyze which new SAP S/4HANA functions you want to use. In this context, which makes more sense: adapting or rethinking existing business processes? Also, consider the simplification list.
• Which parts of the existing landscape do you want to migrate to SAP S/4HANA over what period of time?

With this information, you’ll perform detailed analyses. In general, we recommend the scenarios at the top of Figure 14.1 if comprehensive adaptation work is necessary. The procedures listed in the bottom area are usually considered if the source system already provides a good basis for the target situation and does not need to be changed considerably. In this case, too, you should also think long term; for example, consider whether the current form of your existing business processes (their configurations and existing specific enhancements) must be kept.

By default, your planning should include a careful evaluation of the migration scenario you selected. You can make the right decision and find the procedure best suited to your needs only if you include all technical information from the prechecks, the custom code analysis, a consideration of the forms of new and existing processes, and other information.

Because the final choice of migration scenario is based on numerous specific factors, SAP provides various support services. We recommend using the Innovation Strategy & Roadmap service to obtain a specific recommendation for your situation. Figure 14.2 provides a rough overview of the services in the different phases of the migration project.

Figure 14.2    SAP Services for Migrating to SAP S/4HANA

The Roadmap Viewer provided by SAP is a detailed checklist for the concrete planning and implementation of your SAP S/4HANA transformation process. You can find the Roadmap Viewer at https://go.support.sap.com/roadmapviewer. Of course, you can also implement your planning without using the SAP services, which we’ll discuss next.