For organisations running SAP ECC, the question is not whether to move but how. SAP has set the end of 2027 as the end of mainstream maintenance for SAP ERP 6.0 on recent enhancement packages, with optional extended maintenance available for an additional fee until the end of 2030. After that, systems fall back to customer-specific maintenance, a more limited level of support that does not include new legal and regulatory updates.
Many organisations treat this as a technical upgrade with a deadline. That is understandable, but it wastes an opportunity. Moving to SAP S/4HANA touches finance, supply chain, procurement and reporting at once, and the choices made in the programme will shape how the business runs for many years. It deserves to be run as a business decision.
Know your real deadline
The dates above are SAP’s, but your effective deadline is usually earlier. A large S/4HANA programme takes considerable time from decision to go-live, and it depends on scarce people: internal key users who also have day jobs, and experienced SAP specialists whom many other organisations will need at the same time. Plan backwards from the date you want to be live, not from the date support ends.
SAP also offers a transition option for large, complex customers on a RISE with SAP journey. Under this SAP ERP, private edition, transition option, ECC systems moved into SAP’s private cloud by the end of 2030 can keep running for a limited further period while the move to S/4HANA is completed. It is a cloud subscription with conditions, not a general extension of on-premises maintenance, so understand it well before relying on it.
Choosing an approach
There are three broad approaches, each with real trade-offs:
- Greenfield (new implementation): start fresh on S/4HANA, redesign processes around the standard, and migrate only the data you need. It offers the most room to simplify, but brings the most change for users and the heaviest demand on the business.
- Brownfield (system conversion): convert the existing ECC system, including history and custom code, to S/4HANA. It is usually faster and less disruptive for users, but carries over complexity and old process design unless you clean them up deliberately.
- Selective data transition (sometimes called bluefield): build a new S/4HANA system and move selected data, company codes or history, often using specialist tools. It is a middle ground, for example harmonising processes while keeping history, but needs specialised expertise and careful planning.
The right choice depends on how well your current processes serve the business, how much custom code you carry, how many systems need consolidating and how much change the organisation can absorb. Large groups often combine approaches across business units.
Clean core, clean data and integrations
SAP’s clean core principle means keeping the ERP system as close to standard as possible, and building extensions through stable, upgrade-safe interfaces, often on SAP Business Technology Platform, rather than modifying the core. This makes future upgrades smaller and lets you adopt new SAP functionality without rework. In practice it takes discipline: every custom development should be challenged on whether it gives genuine differentiation or simply recreates something the standard already does.
Data deserves the same attention. Duplicate customers and suppliers, inconsistent material master data and old open items make every migration harder and undermine reporting afterwards. Start cleansing early, appoint data owners in the business, and archive what does not need to move.
Integrations are the other common blind spot. ECC typically sits at the centre of many interfaces to warehouse, CRM, banking, e-invoicing and reporting systems. Map them early and decide which to rebuild on modern APIs and an integration platform, so the new core stays clean.
Deployment options, including RISE with SAP
RISE with SAP is SAP’s bundled offering, combining SAP S/4HANA Cloud, infrastructure, technical operations and supporting tools under one subscription contract. One contract and close alignment with SAP’s roadmap are real advantages. The trade-offs are less control over infrastructure and timing, and a long-term commitment that needs careful negotiation.
Alternatives include running SAP S/4HANA on your own infrastructure, or on a public cloud platform with a managed service partner of your choice. Commercial terms differ between these options, so compare total cost over the full contract period, flexibility and what is actually included, not just the headline offer.
AI is part of this picture. SAP’s assistant, Joule, and embedded AI features can help users find information, automate routine tasks and support developers. SAP has tied much of its AI capability to its cloud offerings, so check which features your chosen edition and contract include. Treat AI as an option to evaluate against concrete use cases, not as a reason on its own to pick a deployment model.
Testing and change management decide the outcome
The technical cutover is rarely what goes wrong. Problems come from processes that were not tested end to end, users who were not prepared, and reports that no longer show what finance expects. A few practices make a real difference:
- Test the business, not just the system: run end-to-end scenarios such as order-to-cash, procure-to-pay and period-end close, with realistic data and key users involved.
- Automate regression testing: S/4HANA receives regular updates, and automated tests make each one cheaper and safer.
- Rehearse the migration: run several mock data migrations and cutovers, measuring and improving each time.
- Invest in change management: explain why processes change, train by role, and support super-users who can help colleagues after go-live.
- Define business outcomes up front: for example a faster close, better inventory visibility or fewer manual reconciliations, and track them after go-live.
How Altechy can help
Our ERP Readiness Assessment is a fixed-scope, four-week assessment of your current ERP, custom code, integrations and data quality. It compares migration approaches and platform options and ends with a high-level programme plan and a business case for management. Our Integration & APIs specialists can map and modernise the interfaces around your ERP, with Altechy coordinating the partners involved as your single point of contact.
To discuss where your own SAP journey should start, book a free 60-minute idea session.