Custom Code Migration: Scoping, Remote ATC and Adaptation

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Custom code migration checklist

• Start SCMON in production early; aggregate with SUSG; cover a full business year including year-end.
• Scope with owners: adapt, retire, back to standard or redesign; where-used check every table before retiring it.
• Deletion transport for unused code, applied by SUM; back the code up with gCTS first.
• Central check system: notes from SAP Note 2436688; stubs in ED1; current simplification database (SAP Note 2241080).
• Run S4HANA_READINESS_REMOTE or the release variant for your target; restrict to scope; fix or exempt priority 1 and 2.
• Group findings by SAP Note and pattern; split before-conversion and after-conversion fixes; list dynamic code for testing.
• SPDD during SUM; in SPAU reset obsolete notes first, then modifications; keep transports small and traceable.
• Quick fixes in ADT for known patterns; sample-review, re-run ATC, check offsets and fixed-length layouts.
• Test by risk: closed-period comparison with ECC, runtime checks (SQLM, SWLT, ST05, SAT), ABAP Unit with test doubles.
• Sign-off: clean in-scope ATC, owners agreed retirements, adaptation in transports, comparisons passed, regression coverage.