Introduction
With this blogpost I like to give an overview about the topic
"S/4 HANA Transformation with Dual Maintenance and Retrofit". In a future blog post I will describe the topic from a technical perspective.
Starting point for existing SAP customers who want to migrate to S/4 HANA
Most of the customers have an existing SAP ECC landscape in place. Let's call this landscape
"The maintenance track".
At the same time, a second landscape is being built for S/4 HANA. Let's call this landscape
"The project track".
During the project period, there are now two landscapes that have to be maintained at the same time. This is a very common use case for most of the SAP customers.
I now would like to use this introduction to explain the retrofit topic.

Retrofit
Dual Maintenance
The following graphic illustrates a dual landscape with the maintenance track and the project track. Every change in the maintenance track needs to be checked whether this is also relevant for the project landscape. This can be done with the support of retrofit (blue arrow).

Dual Maintenance
Possible solutions to keep both maintenance track and project track in sync
- Implementation of an organizational, non-system-supported solution
- Implementation of dual maintenance workflow and Solution Manager ChaRM with Retrofit
- Implementation of dual maintenance workflow with Solution Manager Focused Build and ChaRM with Retrofit
The organizational process
The following graphic illustrates the organizational process for a change which is starting in the maintenance track.

The organizational process
The Solution Manager Retrofit solution
If you choose the system-supported solution, you can decide for each change in the retrofit queue which option you want to perform.
This will give you also the benefit, that no change is forgotten and will be missing in the S/4 HANA project track.

Retrofit queue with explanation
Conclusion
As I mentioned in the introduction, this scenario will be relevant for almost all SAP customers which transform their landscape to S/4 HANA.
I strongly recommend to use the lead time now and think about how you would like to handle the two parallel system landscapes and be well prepared during the S/4 HANA project and also later in operations.
That's all for the moment for the topic "Dual Maintenance" and "Retrofit". I will describe the solution from a technical perspective in a later blog post.
Happy retrofitting!
#RetroIsStillCool