Modifications & enhancements in ECC = brownfield S/4 migration approach?

[former_member815285]

Hi,

my company has embarked on the S/4 HANA migration journey with the overall ambition of achieving a clean core and going back to standard. However, we are migrating from and old ECC system with a history of 25 years of enhancements and modifications. In Procurement & Logistics alone, these 25 years have led to a total of almost 24.000 custom objects, hundreds of user exits and enhancement objects as well as thousands of custom codes on tables and structures. Unfortunately, understanding the reasoning behind each of these adaptations is a never-ending task as documentation is spread across different systems or altogether missing and people having been responsible for it have long retired.

Our project timeline does not allow for going through each and every object and understand what is does and why it is there. We have started looking into certain customizations and it can take hours or even days to find out details on complex cases. Is the inevitable conclusion then that we have to go with a brownfield approach where we take all of our customizations with us and then slowly over time remove obsolete solutions?

One alternative could be to start drawing our processes from scratch and investigate where we might need customizations but we believe there is an extremely high risk that we overlook certain customizations that are essential for the business that would stop operations if missing.

We would like to achieve a clean core, but it seems like mix and match is not a viable option for us. Has anyone faced similar challenges and could share how they have been tackled?

Thank you!

[Ryan-Crosby · Accepted solution]

Hi Dominik,

With 24,000+ custom objects, and history you won't achieve a clean core with a brownfield approach. I have been there previously with another company of doing the endless analyzing, and having to make assumptions in many cases about why some objects even exist (Some objects even pre-dating the 3.0 era). In my experience, the idea of removing obsolete solutions is futile because most of your time ends up being spent either keeping the lights on, or expanding to solve a new problem. The only option to achieve a truly clean core is to go with greenfield, and customize where only necessary, but that requires engagement from the business, and a commitment to adopt best practice to the extent possible.

Regards,

Ryan Crosby