What is the "Obsolete function modules" issue in S/4HANA migration?

Usage of function modules flagged as obsolete in SAP S/4HANA simplification list. Obsolete FMs may not exist or behave differently in S/4HANA. Released API replacements exist.

How much effort does it take to fix "Obsolete function modules"?

Remediation effort is rated M — Medium (days). Severity: MEDIUM.

Which tool checks for Obsolete function modules automatically?

The s4ready.ai A1 Readiness Scanner checks for Obsolete function modules (and 29 other rules) automatically across your custom ABAP codebase. Results include object-level findings with severity and effort estimates.

MEDIUM Effort: M — Medium (days) Deprecated APIs

How to remediate: Obsolete function modules

Usage of function modules flagged as obsolete in SAP S/4HANA simplification list.

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What changes in S/4HANA

Obsolete FMs may not exist or behave differently in S/4HANA. Released API replacements exist.

Before and after: ABAP code example

Before (ECC)

* ECC: FM flagged as obsolete in simplification list
CALL FUNCTION 'HR_GET_LEAVE_DATA'
  EXPORTING
    pernr   = lv_pernr
  IMPORTING
    result  = lt_leave.

After (S/4HANA)

* S/4HANA: check released replacement in API hub
* Use the ABAP Cloud API or released RAP BO
* Verify replacement name in SAP Business Accelerator Hub
* Example pattern with released class:
DATA(lo_api) = NEW cl_hcm_leave_api( ).
lo_api->get_leave_data(
  EXPORTING iv_pernr = lv_pernr
  IMPORTING et_leave = DATA(lt_leave) ).

Effort estimate and common pitfalls

Effort estimate

M — Medium (days)

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

! Missing related objects that contain the same pattern
! Not testing edge cases after replacing the API
! Skipping regression tests for dependent programs

Related rules to check

HIGH L

Deprecated customer BAPIs

BAPI_CUSTOMER_* function modules are deprecated. Use Business Partner APIs in S/4HANA.

HIGH L

Deprecated vendor BAPIs

BAPI_VENDOR_* function modules are deprecated. Use Business Partner APIs.

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 Obsolete function modules — across your custom ABAP objects and produces a prioritised remediation backlog.

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