Clean Core
What it is
SAP's principle that the digital core (S/4HANA) is kept standard and upgrade-stable: customisation happens through released extension points and side-by-side apps, never by modifying SAP objects. It spans not just code but data, processes, integration and operations.
Why it matters for Clean Core
A clean core is what lets you take SAP's continuous updates without a regression project every time. It is the precondition for ABAP Cloud, for RISE, and for SAP's AI (Joule) reaching your custom logic safely.
Common pitfall
Treating Clean Core as a code-only, all-or-nothing switch. It's a spectrum measured by ATC, and it covers extensibility, data, integration and operations — not just whether your reports compile in ABAP Cloud.