Häufig gestellte Fragen
When is brownfield the right choice, and when greenfield?
Brownfield is recommended when existing processes remain viable, data continuity and historical transaction data are important, and only a short project window is available. Greenfield, by contrast, makes sense when workflows are to be fundamentally redesigned, accumulated customizing has become a burden, or a deliberate fresh start with standard processes is desired. In practice, according to industry observations, more companies moving to SAP S/4HANA opt for brownfield or hybrid paths than for a complete greenfield rebuild. The specific form depends on the ERP system, industry, and customizing depth and should be aligned with the respective vendor.
What risks does a brownfield migration entail?
The biggest risk is that technical debt and outdated processes are carried over into the new system unexamined, because the purely technical conversion does not streamline workflows by itself. Custom code can sometimes block standard functions and complicate future releases, and undocumented custom developments can cause errors during the transition. A dirty data foundation is converted along with everything else too, which is why upstream data cleansing is considered a key success factor. Many projects therefore flank the migration with a selective clean-up program to reduce legacy baggage in a targeted way.
How long does a brownfield project take?
Depending on system size and customizing depth, a brownfield conversion typically takes around 6 to 12 months and is thus usually significantly shorter than a greenfield rebuild, which often stretches over 18 to 36 months. The time advantage arises because the process design and data model do not have to be conceived from scratch. Experience shows that ERP projects nevertheless frequently exceed their original schedule, so realistic buffers should be planned in. A dedicated internal project manager with decision-making authority and high availability is considered an important lever for staying on schedule.
What happens to custom code and customizing in a brownfield migration?
With brownfield, customizing and customer-specific extensions are carried over in principle but must be adapted to the data structures and functional logic of the new platform. In an SAP S/4HANA conversion, this happens for instance via a custom code analysis and the adaptation of ABAP modifications using the tools provided for this purpose, as well as by checking so-called Simplification Items, which flag changed or discontinued functions. Experience from SAP environments shows that only part of the original custom code is actually used productively going forward, while unused adaptations are weeded out in the course of the analysis. An honest inventory of which custom developments are business-critical and which can be replaced by standard functions is therefore essential.
Is a selective migration or bluefield approach a sensible alternative?
Yes, between pure brownfield and greenfield there are hybrid forms, often referred to as selective data migration or bluefield. A new system is set up into which selected data sets and processes are deliberately transferred, while other areas are consciously rebuilt and cleaned up. This hybrid path combines the data continuity of brownfield with the process modernization of greenfield and is increasingly used, but it is methodologically more demanding. The specific form varies by industry, company size, and customizing depth of the respective ERP setup and should be evaluated project by project.
What role does the end of maintenance for SAP ECC play in brownfield migrations?
For existing SAP customers, the migration pressure has a concrete deadline: as things currently stand, regular mainstream maintenance for SAP ECC 6.0 (EHP 6 to 8) expires at the end of 2027, and paid extended maintenance is offered until the end of 2030. Because brownfield is the fastest route to the successor platform S/4HANA, many companies choose this approach primarily for timely technical compliance. Those who instead want to fundamentally transform their business processes are more likely to accept a greenfield or selective path, which requires more lead time. Since maintenance deadlines and conditions can change and differ by release, the current status and individual contract terms should always be verified directly with the vendor.