What is the "SAP core modification (includes Z-copy)" issue in S/4HANA migration?

Direct modification of SAP standard repository objects or Z-copies of standard programs. Core modifications are not supported in S/4HANA Public Cloud. On-prem upgrades reset modifications.

How much effort does it take to fix "SAP core modification (includes Z-copy)"?

Remediation effort is rated XL — Extra Large (2+ weeks). Severity: CRITICAL.

Which tool checks for SAP core modification (includes Z-copy) automatically?

The s4ready.ai A1 Readiness Scanner checks for SAP core modification (includes Z-copy) (and 29 other rules) automatically across your custom ABAP codebase. Results include object-level findings with severity and effort estimates.

CRITICAL Effort: XL — Extra Large (2+ weeks) Clean Core

How to remediate: SAP core modification (includes Z-copy)

Direct modification of SAP standard repository objects or Z-copies of standard programs.

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What changes in S/4HANA

Core modifications are not supported in S/4HANA Public Cloud. On-prem upgrades reset modifications.

Before and after: ABAP code example

Before (ECC)

* ECC: Z-copy of SAP standard (e.g., copied MF45AFVB)
FUNCTION zmf45afvb_modified.
  " SAP standard code + custom additions
  " This will be overwritten on every SAP upgrade
ENDFUNCTION.

After (S/4HANA)

* S/4HANA: extension via released BAdI or Substitution
* Identify the BAdI replacing the modified standard spot:
*   SE18 > search by package of original FM
* Implement as BAdI enhancement:
CLASS zcl_sales_doc_save DEFINITION PUBLIC CREATE PUBLIC.
  PUBLIC SECTION.
    INTERFACES if_ex_v45a_badi.
  PROTECTED SECTION.
  PRIVATE SECTION.
ENDCLASS.

Effort estimate and common pitfalls

Effort estimate

XL — Extra Large (2+ weeks)

Estimate is per affected object. Total effort scales with the number of occurrences in your codebase. Use the A1 scan to get an object-level count before estimating the full project.

Common pitfalls

! Architectural dependencies that require multiple teams
! Data migration requirements alongside code changes
! Extended regression and integration test cycles
! Potential need for parallel run before cutover

Related rules to check

CRITICAL XL

MODIFY on SAP standard tables

Direct INSERT/UPDATE/MODIFY/DELETE on SAP standard tables bypasses business logic and breaks upgrade stability.

HIGH L

Implicit enhancements on SAP standard

Implicit enhancement points inside SAP standard programs. These survive upgrades but hide dependencies.

HIGH L

ABAP Cloud restricted object access

Access to SAP internal objects without C1 release status. These are blocked in ABAP Cloud.

Find every instance of this issue in your codebase

The A1 scanner checks all 30 compatibility rules — including SAP core modification (includes Z-copy) — across your custom ABAP objects and produces a prioritised remediation backlog.

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