ABAP Cloud Migration & Clean Core Level Remediation

Guide for systematically raising the clean core level of classic ABAP custom code — eliminating Level D, minimizing Level C, and moving toward Level A (ABAP Cloud).

Terminology note: the former 3-tier extensibility model is superseded by the clean core level concept (A, B, C, D). Migration is no longer "get everything to Tier 1" — it is "eliminate Level D, minimize Level C, accept stable Level B, target Level A for new work". See the abap-cloud skill for the level definitions.

Workflow

1. Assess current state: run ATC clean core checks on existing code
2. Classify findings by level: priority 1 → Level D, priority 2 → Level C, priority 3 → Level B
3. Prioritize remediation: Level D first (must fix), then Level C (minimize), then Level B (monitor)
4. Choose a transformation option: retire · renovate side-by-side · renovate on-stack · adapt
5. Implement replacements: released APIs, classic APIs, or wrappers with a single ATC exemption
6. Validate: re-run ATC checks, verify no priority 1/2 findings remain, test functionality

Migration Assessment

Running ATC clean core checks