To leave SAP ECC before the 2027 end-of-maintenance deadline, you need to follow three steps: assess your current landscape and readiness, choose your migration approach (greenfield or brownfield), and execute your transition with structured data migration, testing, and cutover management. Most organisations need at least 18 to 24 months to complete this process, which means 2026 is the last realistic year to start if you want to go live before support ends. The sections below walk through each step in detail and answer the most common questions about the SAP ECC sunset.
Why is SAP ending support for ECC in 2027?
SAP is ending mainstream maintenance for SAP ECC because it is replacing the platform entirely with SAP S/4HANA, its next-generation ERP built on the in-memory HANA database. SAP has set the end-of-maintenance date for ECC at the end of 2027, after which SAP will no longer provide standard updates, security patches, or legal compliance changes for the platform.
SAP ECC has been the backbone of enterprise operations for decades, but the architecture was not designed for the speed and flexibility that modern businesses need. SAP S/4HANA offers real-time processing, a simplified data model, and a more modern user experience through SAP Fiori. By ending ECC support, SAP is pushing its entire customer base to migrate.
For organisations still running ECC, this is not just a technical upgrade. It is a full business transformation that touches processes, data structures, integrations, and the people who use the system every day. That scope is exactly why starting early matters so much.
How much time does an SAP ECC migration actually take?
An SAP ECC to S/4HANA migration typically takes between 18 and 36 months, depending on the size of the organisation, the complexity of existing processes, and the migration approach chosen. Smaller organisations with simpler landscapes can sometimes complete the move in 12 to 18 months, but large multinationals with multiple systems, countries, and custom developments rarely finish in under two years.
The timeline breaks down across several phases. A maturity assessment and readiness evaluation typically takes one to three months. Design and planning, including As-Is and To-Be analysis, adds another two to four months. The build, configuration, and testing phase is usually the longest, running six to twelve months. Data migration preparation runs in parallel throughout. And cutover and go-live, while measured in days or weeks, requires months of preparation to execute safely.
Given that the SAP ECC end-of-maintenance deadline falls at the end of 2027, organisations that have not yet started their migration by 2026 are already in a tight window. Waiting until late 2026 to begin makes a clean go-live before the deadline extremely difficult.
What are the 3 steps to leave SAP ECC before 2027?
The three steps to leave SAP ECC before the 2027 deadline are: assess your readiness, define your migration approach, and execute your transition with structured project management, data migration, and cutover management. Each step builds on the previous one, and skipping or rushing any of them increases the risk of delays, cost overruns, or a failed go-live.
Step 1: Assess your readiness
Before committing budget or building a roadmap, you need to understand where your organisation actually stands. This means evaluating your current ERP landscape, the quality of your data, the maturity of your processes, and the capacity of your internal team to support a transformation of this scale.
A structured maturity assessment gives you a clear baseline. It identifies gaps, risks, and priorities before any design work begins. We typically start here with every client because it prevents organisations from committing to a migration scope that does not match their actual readiness. Without this step, you risk designing for a future state that your organisation cannot yet support.
Step 2: Define your migration approach
Once you know where you stand, you choose between a greenfield or brownfield migration (explained in the next section). This decision shapes everything that follows: the timeline, the cost, the level of process change required, and the change management effort needed to bring your organisation along.
At this stage, you also define scope, build your project team, and set up your governance model. Organisations that skip proper program management at this point often find themselves managing conflicting workstreams, unclear ownership, and stakeholder misalignment later in the project.
Step 3: Execute your transition
Execution covers the build, data migration, testing, and cutover phases. This is where the bulk of the timeline sits. Data migration management is one of the highest-risk activities in this phase. Poor data quality or incomplete migration can cause serious operational disruption at go-live. Rigorous testing, including both technical and business readiness testing, is what gives you confidence that the system is ready before you switch over.
Cutover is the final and most time-pressured step. A well-planned cutover runs to a detailed runbook, with real-time monitoring and clear decision points. It also includes hypercare support in the days and weeks after go-live, so your team has expert backup when they need it most. You can explore our full range of services to see how each phase is covered end-to-end.
What is the difference between greenfield and brownfield SAP migration?
A greenfield SAP migration means building your S/4HANA environment from scratch, without carrying over existing configurations or customisations. A brownfield migration means converting your existing ECC system to S/4HANA, preserving your current setup and migrating it into the new platform. The right choice depends on how much your organisation wants to standardise its processes versus preserve what it already has.
Greenfield gives you a clean slate. You redesign processes based on SAP best practices, reduce technical debt, and build a leaner, more standardised system. The trade-off is that it takes longer, costs more, and requires significant change management because users are learning new processes, not just a new interface.
Brownfield is faster and less disruptive in the short term. You keep your existing processes and data structures and convert them into S/4HANA. The risk is that you carry over inefficiencies, custom code, and legacy complexity into the new system, which can limit the business value you get from the migration.
Many organisations choose a hybrid approach, sometimes called a selective data transition, where they take a greenfield approach to processes but migrate historical data from the existing system. This combines the benefits of process redesign with continuity of data access.
What happens if you stay on SAP ECC after 2027?
If you stay on SAP ECC after the 2027 end-of-maintenance date, SAP will no longer provide standard support, security patches, or legal and regulatory updates for your system. Your ECC environment will continue to run, but you will be operating on unsupported software with growing security and compliance risks.
SAP does offer extended maintenance options, but these come at a significant additional cost and only delay the inevitable. They do not add new functionality or resolve the underlying issue that ECC is an ageing platform that will fall further behind S/4HANA with every passing year.
Beyond the direct risks, staying on ECC after 2027 creates a competitive disadvantage. Organisations that have completed their SAP S/4HANA migration will benefit from real-time analytics, improved automation, and a more agile system architecture. Those still on ECC will be working with a platform that is no longer evolving.
The practical message is straightforward: the longer you wait, the more expensive and disruptive the migration becomes, and the fewer experienced consultants and partners will be available as the deadline approaches and demand peaks.
How Optinus helps you migrate from SAP ECC before 2027
We work with multinational organisations at every stage of the SAP ECC to S/4HANA migration journey. Our consultants have hands-on experience from real ERP migrations at leading multinationals, not just theoretical frameworks, and we cover the full spectrum from maturity assessment to post-go-live hypercare under one roof.
- Maturity assessment to give you a clear baseline before any budget or roadmap is committed
- Program and project management to keep scope, timelines, and stakeholders aligned throughout
- Data migration management with rigorous As-Is/To-Be analysis and testing to prevent data loss
- Cutover management with real-time monitoring, a detailed runbook, and hypercare after go-live
- Change management to drive genuine user adoption, not just deliver training
- Available on-site and remote, across the Netherlands, Belgium, and internationally
If you are running SAP ECC and the 2027 deadline is on your radar, now is the time to act. Get in touch with our team to discuss where your organisation stands, or learn more about what we do and how we approach ERP transformation from start to finish.
Gerelateerde artikelen
- What happens to your data when you migrate from Dynamics AX?
- How do you manage transformation action items?
- What is the difference between program and project sponsors?
- How do you handle system integration during business transformation?
- What does a successful Microsoft Dynamics implementation look like?
