SAP ECC to S/4HANA before 2027
Cohash helps SAP ECC customers move to S/4HANA before ECC mainstream maintenance ends in 2027. We size custom ABAP and simplification items, help pick conversion, new build or selective data transition, run customer-vendor integration to business partners, rebuild PI/PO interfaces on Integration Suite and rehearse downtime. Identity and authorization work, including the SAP Identity Management replacement, runs as part of the same plan.
- 01Readiness and custom code
- 02Pick the path
- 03Business partner and finance prep
- 04Integration rebuild
- 05Mock conversions
- 06Roles, cut-over and hypercare
The story
Told without the client's name or anything that could identify them.
A chemicals manufacturer ran SAP ECC 6.0 with a large body of custom ABAP and most of its integrations on PI/PO, both facing the end of mainstream maintenance in 2027. Extended maintenance fees were in the next budget and nobody had approved them. We started with SAP Readiness Check and an ABAP Test Cockpit run against usage data, so unused code was retired instead of fixed, and chose the path per company code. After business partner conversion, interfaces rebuilt on Integration Suite and repeated mock conversions to measure downtime, the business went live on S/4HANA with Fiori roles provisioned through the identity platform and hypercare through month-end close.
why it was urgentMainstream maintenance for ECC 6.0 ends at the end of 2027, with optional extended maintenance to the end of 2030. After that, SAP ERP, private edition offers business continuity from 2031 to 2033, but only for systems moved by 31 December 2030. S/4HANA itself is committed to the end of 2040. PI/PO is its own problem, since the NetWeaver 7.5 release under it also leaves mainstream maintenance in 2027.
- openSomebody put extended maintenance fees in next year's budget. Nobody has approved them.
- recurringCustomer and vendor master data has duplicates that would fail business partner conversion.
- blockedThousands of custom ABAP objects, and no one knows how many are still used.
- openPI/PO carries most of the interfaces, and it's on the same 2027 clock as ECC.
The estate, before and after
Before: SAP ECC 6.0 with PI/PO on the 2027 deadline
ECC 6.0 in SAP GUI, with custom ABAP whose use nobody knew and duplicate customer and vendor masters. Interfaces ran on PI/PO and users came from SAP Identity Management. Every one of those pieces hit end of mainstream maintenance in 2027.
Read the diagram as text
- Business users → SAP ECC 6.0: transactions
- SAP Identity Management → SAP ECC 6.0: user provisioning
- Custom ABAP → SAP ECC 6.0: custom logic
- Customer and vendor masters → SAP ECC 6.0: master data
- SAP ECC 6.0 → SAP PI/PO: IDocs
- SAP PI/PO → Trading partners: EDI
- SAP PI/PO → Non-SAP applications: interfaces
After: SAP S/4HANA with Integration Suite and governed roles
Fiori apps on S/4HANA, with one business partner where there used to be a customer and a vendor. SAP Integration Suite carries the interfaces, and users and roles come from the identity platform.
Read the diagram as text
- Business users → SAP S/4HANA: Fiori
- Entra ID or SailPoint → SAP S/4HANA: users and roles
- Business partners → SAP S/4HANA: master data
- SAP S/4HANA → SAP Integration Suite: IDocs and OData APIs
- SAP Integration Suite → Trading partners: EDI
- SAP Integration Suite → Non-SAP applications: APIs
How we run it, phase by phase.
6 phases take you from SAP ECC 6.0 (Business Suite 7) to SAP S/4HANA (private cloud or on-premise). Each one ends with something you can check before the next starts. As you scroll, the blocks show the estate moving across.
- phase 01
Readiness and custom code
Run SAP Readiness Check and the simplification item checks, then analyze custom ABAP with the ABAP Test Cockpit and usage data so unused code is retired instead of fixed.
- phase 02
Pick the path
Choose system conversion, a new implementation or selective data transition per company code. Process fit decides a lot, along with how much history you need and how much custom code survives.
- phase 03
Business partner and finance prep
Run customer-vendor integration to create business partners, cleaning master data until it passes. Get finance ready for the universal journal and new asset accounting.
- phase 04
Integration rebuild
Inventory the PI/PO interfaces and IDocs, move them onto SAP Integration Suite or APIs, then retest every partner connection.
- phase 05
Mock conversions
Run conversions on production-sized copies with the Software Update Manager, more than once. Measure downtime and test finance reconciliation after each run.
- phase 06
Roles, cut-over and hypercare
Rebuild authorizations for Fiori apps and changed transactions, provision users through the identity platform, then cut over and support month-end close in hypercare.
What the client got
What changed for the client once the work was done. Described, not scored: we don't publish client figures.
- result 01
Only custom code that was used came across
Usage data plus ABAP Test Cockpit findings gave every custom ABAP object a retire, fix or rebuild decision. Code nobody used was dropped rather than fixed.
- result 02
Customers and vendors are business partners
We kept cleaning master data until customer-vendor integration passed, and finance is on the universal journal and new asset accounting.
- result 03
Interfaces run on Integration Suite or APIs
PI/PO interfaces and IDocs were moved and every partner connection retested. The integration layer isn't stuck on NetWeaver 7.5.
- result 04
Downtime was measured before cut-over
We ran mock conversions on production-sized copies several times, timing the Software Update Manager and checking finance reconciliation after each.
- result 05
Roles were ready for Fiori on day one
Authorizations cover the Fiori apps and the changed transactions. Users are provisioned through the identity platform, and SAP Identity Management is out of the picture.
Risks we plan for
-
Business partner conversion failures
Bad or duplicated customer and vendor records stop the conversion. Data cleanup has to start months before the first mock run.
-
Downtime longer than the business allows
A big database and lots of custom code mean a long conversion. If the first mock overruns, you need lead time to plan something like downtime-optimized conversion.
-
Authorizations break on day one
Transactions change and Fiori apps need catalogs and roles. Users who can't post on go-live morning are the most common hypercare ticket.
-
Integration deadlines collide
PI/PO and SAP Identity Management both reach end of mainstream maintenance in 2027. Running them as side projects risks a converted ERP with unsupported plumbing.
Where AI helps, and where it needs guardrails
SAP keeps adding Joule assistants and agents to its ERP. We use LLMs to triage ABAP Test Cockpit findings and draft remediation for custom code, with a developer approving every transport. Any MCP server that exposes S/4HANA OData APIs to agents should use a technical user with narrow authorizations, read-only by default, with writes routed through normal SAP workflows.
forward deployed engineers →What you're left with
We write these for your setup, and they're working documents. Your team should be able to keep things running from them long after we've gone.
- inventory01
Custom code inventory with retire, fix or rebuild decisions
yours to keep - code02
Path decision per company code with the reasoning written down
yours to keep - document03
Business partner data cleanup tracker and conversion results
yours to keep - inventory04
Interface catalog with target design on Integration Suite or APIs
yours to keep - report05
Mock conversion reports with measured downtime
yours to keep - design06
Role design for Fiori and changed transactions
yours to keep
Platforms and services on this move
Certified engineers, wherever you need them.
Some clients want a project team, some want a couple of engineers on theirs. Either works. Onsite, nearshore or offshore, with handovers across time zones that keep things moving.
Onsite
Engineers at your sites in the US
Nearshore
Overlapping hours with US teams
Offshore
Overnight progress on your backlog
All time zones
Coverage handed over across time zones
01Is it too late to finish before the end of 2027?
Tight, for a large estate starting now. You can take extended maintenance to 2030, or the private edition transition option, which needs you on SAP ERP, private edition by 31 December 2030. We look at size and custom code before saying which route is realistic.
02Conversion or new implementation?
Conversion keeps history and is usually faster when processes still fit. A new build makes sense when the old design is the problem. Selective data transition sits between them. We decide per company code, not once for the whole group.
03Do you also replace SAP Identity Management?
Yes. SAP IdM's maintenance ends in 2027 too, so moving provisioning to Microsoft Entra ID Governance or SailPoint goes in the same plan.
04What drives the cost?
Custom code volume and interface count. Then data quality, how many company codes and countries go live at once, and the downtime the business will accept.
Often on the same roadmap
On-premises Active Directory to cloud-first Microsoft Entra ID
We shrink on-premises Active Directory one application at a time, moving groups, users and app authentication to Microsoft Entra ID as each app is ready.
read the case studyAD FS federation to Entra ID authentication
Converting federated domains from AD FS to Entra ID cloud authentication, moving relying parties app by app and retiring the AD FS farm.
read the case studyAI pilot to production with forward deployed engineers
Taking an AI pilot into production with forward deployed engineers who work with the business team, build evals, connect real systems and hand over cleanly.
read the case studya5a43798 - 01SAP News: maintenance to 2040 and Business Suite 7 dates (4 Feb 2020)news.sap.com ↗
- 02SAP News: SAP ERP, private edition, transition option updatesnews.sap.com ↗
- 03SAP Learning: SAP Process Orchestration to Integration Suite migrationlearning.sap.com ↗
- 04CIO: SAP adds more Joule assistants and agentscio.com ↗
Planning this move?
A 30-minute working session with a senior engineer. No slides.
- The platform and the version you're on
- Where you need to get to, and by when
- What's custom: rules, plugins, integrations
- Any audit finding or deadline driving it