Clean Core Extensibility Levels A-D in Practice

Keep this: job aid

Clean core levels card

• A: released APIs and extension points only (ABAP Cloud, key user tools, BTP on public APIs).
• B: A plus classic APIs that SAP classifies as documented and generally upgrade-stable.
• C: access to SAP internal objects; upgrade risk; review SAP's changelog.
• D: modifications, implicit enhancements, writes to SAP tables, non-recommended objects.
• An extension takes the level of its least clean component; never average.
• ATC: Clean Core checks Usage of APIs (Cloudification Repository) and Allowed Enhancement Technologies; pin the classification file.
• Prioritize remediation by upgrade risk × business criticality vs effort; shared utilities first; retire dead code.
• Wrappers contain risk, they do not remove it.
• New work: A by default; B justified; C exemption with owner and expiry; D board approval and exit plan.
• Prove every remediation: new ATC level plus tests showing unchanged behavior.