Inside What Actually Breaks in Large-Scale S/4HANA Conversions (And How to Prevent It)

Broken Custom ABAP Code in S/4HANA From an engineer’s perspective, one of the first headaches in a brownfield S/4HANA migration is custom ABAP code that no longer runs correctly. Unlike a simple upgrade, S/4HANA introduces a new architecture with a simplified data model and revised logic. Many classic SAP ECC tables and transactions either vanish or behave differently in S/4HANA, meaning some Z-programs that worked fine in ECC may now short-dump or produce incorrect results. Common breakage patterns include: