When companies want to implement SAP S/4HANA, there are two main strategies available to them: the greenfield approach (New Implementation) and the brownfield approach (System Conversion; Re-use).
The greenfield and brownfield approach thus represent different options for converting an SAP ERP system to S/4HANA: With the greenfield approach, companies undertake a completely new installation of the SAP S/4HANA system. The brownfield approach stands for a software upgrade that preserves all data and settings.
There is also selective migration - a middle course between greenfield and brownfield (formerly: landscape transformation). Experts also speak of the color field approach or a hybrid strategy.
Selective migration is a strategic approach based on brownfield. If companies go down this route, SAP experts copy the old system without data and convert it to S/4HANA. This empty system is then filled with legacy data via data migration. The migration can be controlled individually: For example, the specialists migrate only a defined section of data or recode data.
The challenge for companies when introducing S/4HANA is to find the right strategy for implementation in the first step.