SAP ECC 2027 End-of-Support Checklist: Is Your Custom Code Ready?
Mainstream SAP ECC maintenance ends 31 December 2027. This checklist covers the six critical workstreams every SAP customer must address to reach S/4HANA readiness before the deadline.
Mainstream SAP ECC maintenance ends 31 December 2027. Paid extended maintenance runs to 2030 — but waiting has a cost. Here is the practical checklist every SAP customer should be working through now.
Why the deadline is real
SAP ECC (EHP6/EHP8) has been the backbone of enterprise SAP for nearly two decades. After 2027, SAP will no longer release compatibility patches, security fixes, or legal change packages for ECC under mainstream maintenance. Extended maintenance covers critical security patches only — and at a premium.
Customers remaining on ECC face compounding risk: increasing technical debt, loss of access to SAP’s innovation roadmap (embedded AI, Clean Core APIs, BTP), and a migration that becomes more expensive every year it is deferred.
The six workstreams
1. Custom code assessment
Understand what you have before you plan anything else. A full custom code assessment should surface:
- Total Z-objects and Y-objects by type (programs, function modules, classes, enhancements)
- Usage frequency — dead code versus business-critical
- S/4HANA compatibility findings: SELECT *, deprecated tables, pool/cluster JOIN issues, obsolete statements
- Clean Core Score: released API usage vs. modifications vs. deprecated object references
Tool: run the A1 Readiness Scan on your highest-risk custom programs first.
2. SAP Simplification Item review
SAP publishes a Simplification Item Catalog listing objects deprecated or removed in S/4HANA. Your custom code must be checked against this list. Items include:
- Replaced FI/CO tables (BSEG → ACDOCA)
- Deprecated logistics tables (MARA/MARC → I_Material CDS)
- SD table restructuring (VBAK/VBAP → I_SalesDocument)
3. Clean core strategy
Every custom program that touches core tables or internal function modules is a clean-core violation. The remediation path depends on the extension type:
- Key-user extensions: use in-app customising, custom fields, BAdI
- Developer extensions (ABAP Cloud): rewrite to released APIs (C1 status) only
- Side-by-side: move complex logic to BTP extensions consuming released OData V4 APIs
4. Data migration planning
S/4HANA uses a different data model. Key migration objects include:
- Business Partners (merging KNA1/LFA1 into BP)
- Material master restructuring
- Open item migration (accounting documents)
LTMC (LSMW successor) is the standard tool. Plan this workstream early — data quality issues are the #1 go-live blocker.
5. Testing strategy
Every remediated custom object needs ABAP Unit test coverage. Plan for:
- Unit tests for all remediations (A3 can generate these)
- Integration regression testing for business processes
- SIT/UAT scripts aligned to business scenarios (A4 can generate test scripts)
6. Technical infrastructure
- HANA sizing and hardware (or cloud provisioning)
- System landscape transformation tool (SLT) if doing system conversion
- Transport management and cutover planning
Timeline guidance
| Phase | Typical duration |
|---|---|
| Custom code assessment | 2–4 weeks (automated: days) |
| Clean core remediation | 3–6 months (automated: weeks) |
| Data migration build | 2–4 months |
| Testing (SIT/UAT) | 2–3 months |
| Cutover preparation | 6–8 weeks |
With automated tooling, the assessment and remediation phases shrink dramatically. The rest of the timeline is determined by business change management and testing — not technical effort.
Start with a free scan
The fastest way to understand your exposure is a free ABAP readiness scan. Upload or paste a representative custom program and get a Clean Core Score in minutes.
SAP, S/4HANA, ABAP and related marks are trademarks of SAP SE. Verify current SAP maintenance dates against official SAP sources before planning.