SAP migration is the process of moving an organization’s ERP system from SAP ECC to SAP S/4HANA, and for UK enterprises it is no longer a future planning exercise — it is a 2026 execution problem. SAP’s mainstream maintenance for ECC 6.0 ends December 31, 2027, with extended maintenance available only through 2030 for an additional fee, and more than 75% of the UK’s largest businesses run SAP today . Workato is not an SAP migration tool — it does not replace ECC or move core financial data into S/4HANA. It is the orchestration layer that keeps every system around SAP connected before, during, and after the cutover, which is where most SAP migration projects actually lose time. This post covers the deadline mechanics, the three migration approaches UK enterprises are choosing between, and the integration architecture question CIOs are getting wrong.
What Is SAP Migration and Why Is It Urgent for UK Enterprises Now?
SAP migration is the technical and organizational project of moving from SAP ECC to SAP S/4HANA, and it is urgent now because the runway to do it without a maintenance penalty is genuinely short. SAP ERP 6.0 Enhancement Packages 0 through 5 lose mainstream maintenance at the end of 2026; Enhancement Packages 6 through 8 hold mainstream maintenance until the end of 2027. After that, a UK enterprise either completes its move to S/4HANA, pays for extended maintenance (an estimated 2 percentage points, roughly a 9% cost premium, through the end of 2030), or negotiates a bespoke RISE with SAP arrangement reserved for large, complex ECC estates that need more runway than 2030 allows. None of those three options is “do nothing” — every UK enterprise still on ECC has a decision to make in 2026, not 2029.
The real deadline math
The deadline that matters for planning is 2027, not 2030. Extended maintenance is a cost-managed delay, not a solution — it buys time at a premium while security patches, compliance updates, and SAP’s own engineering attention shift toward S/4HANA. A CIO treating 2030 as the real deadline is planning against the wrong number; a migration of any meaningful scale — data, custom code, integrations, testing, cutover — needs 18 to 36 months of runway, which means enterprises starting a migration in 2027 are already behind.
How Many UK Enterprises Are Affected by the SAP ECC Deadline?
Thousands of UK organizations run SAP today, spanning retail, financial services, energy, manufacturing, and the public sector, and the large majority of them are still on ECC rather than S/4HANA. Public directories list over 5,000 UK companies actively running SAP , including household names like Unilever, HSBC, BP, Tesco, Sainsbury’s, BT Group, Diageo, Marks & Spencer, Rolls-Royce, and Jaguar Land Rover. Most of these ECC deployments date to the late 1990s or early 2000s and carry a decade or more of custom ABAP development layered on top of standard SAP processes — the exact profile that makes a migration decision harder, not easier, the longer it’s deferred.
Why scale compounds the timeline problem
A large UK enterprise’s SAP footprint rarely stands alone — ECC typically sits at the center of a web of CRM, e-commerce, warehouse management, HR, and finance systems that all depend on data flowing in and out of SAP on a predictable schedule. The migration decision is not just “which S/4HANA path do we choose” — it’s “how many connected systems break if we get the cutover wrong,” and that second question is the one most migration timelines underestimate.
What Are the Three SAP Migration Approaches — Brownfield, Greenfield, Bluefield?
The three SAP migration approaches — brownfield, greenfield, and bluefield — differ in how much of the existing ECC configuration and custom code survives the move to S/4HANA. A brownfield migration converts the existing SAP environment in place, preserving most configuration and custom development, which makes it the fastest technical route to S/4HANA. A greenfield implementation builds S/4HANA from scratch against SAP’s Best Practices templates, discarding legacy configuration entirely in favor of a clean, standardized build. A bluefield approach is the hybrid: it selectively migrates specific data, company codes, and processes while leaving obsolete configuration behind, letting an enterprise redesign what’s broken and keep what works.
Which approach UK enterprises are actually choosing
Per 2026 ISG research, brownfield accounts for roughly 34% of migration choices and greenfield around 18%, with bluefield now outpacing greenfield as the preferred approach for enterprises seeking meaningful process improvement without a full rebuild . The same research found nearly 60% of SAP migration projects run over budget or behind schedule — a figure that should temper any CIO’s confidence in a fixed-date, fixed-cost migration plan, regardless of which approach is chosen.
Which SAP Migration Approach Is Right for a UK Enterprise?
The right SAP migration approach depends on how much of the existing ECC estate is worth preserving versus how much technical debt has accumulated in custom code and configuration. A UK enterprise with a relatively clean ECC build and strong reasons to preserve institutional process knowledge is a brownfield candidate — fastest to execute, lowest process disruption, but it carries legacy technical debt forward into S/4HANA. An enterprise whose ECC system has drifted far from standard SAP processes, or whose business has fundamentally changed since the original implementation, is a stronger greenfield candidate — a clean foundation, but the highest cost and the most organizational change to absorb. Bluefield sits between the two, and 2026 adoption trends suggest most UK enterprises are landing there: enough transformation to fix what’s broken, enough preservation to avoid rebuilding what already works.
The decision most CIOs get backward
Most SAP migration planning starts with the ERP question — which approach, which timeline, which system integrator — and treats the surrounding application estate as an afterthought to be handled “closer to cutover.” That ordering is backward. The systems connected to SAP (CRM, commerce, warehouse, HR, finance reporting) need an integration architecture decided early, because every one of them has to keep working through a migration that, per the ISG data above, is more likely than not to run long.
What Role Does Integration Play in an SAP Migration Project?
Integration determines whether a SAP migration disrupts the business or stays invisible to it, because the systems around ECC and S/4HANA don’t pause while the ERP core is being rebuilt. A CRM system still needs customer and order data. An e-commerce platform still needs inventory and pricing. A warehouse management system still needs fulfillment status. None of that data movement stops for an 18-month migration project — which means every point-to-point integration built against ECC’s specific API surface, IDoc structure, or custom ABAP function module needs a plan for what happens when S/4HANA’s data model and APIs replace it.
Why point-to-point integrations break during a migration
Point-to-point integrations built directly against ECC are typically hardcoded to ECC’s specific tables, IDocs, and custom RFCs, and none of that maps cleanly onto S/4HANA’s different data model, even in a brownfield conversion. Every one of those integrations becomes a migration line item that must be rebuilt, retested, and re-validated on its own timeline — multiplied across every connected system, this is a major, frequently underestimated driver of the schedule overruns ISG’s 2026 research documents.
How Do Surrounding Systems Stay Connected During an ECC-to-S/4HANA Cutover?
Surrounding systems stay connected during an ECC-to-S/4HANA cutover through an integration layer that sits above both ERP versions, so CRM, commerce, and reporting systems talk to a stable connection point rather than directly to whichever SAP system happens to be live that week. This is the core architectural decision that separates a controlled, phased migration from a disruptive big-bang cutover: instead of every connected system pointing directly at ECC and then being individually re-pointed at S/4HANA on cutover day, an orchestration layer manages the routing, so ECC and S/4HANA can run in parallel during a phased transition without every downstream system needing to know which one is authoritative at a given moment.
The coexistence period is where most risk lives
Almost no SAP migration is a single overnight cutover — most run a coexistence period where some modules, company codes, or regions are live on S/4HANA while others remain on ECC, sometimes for months. That coexistence window is where integration risk concentrates: a CRM system pulling customer data needs to know which SAP instance is authoritative for which customer, region, or process, and that logic is far easier to manage centrally in an orchestration layer than to hardcode into every individual point-to-point connection.
What Should a Phased SAP Migration Integration Architecture Look Like?
A phased SAP migration integration architecture routes each connected system through a single orchestration layer that can direct traffic to ECC or S/4HANA per module, region, or company code, rather than requiring every downstream system to be individually re-pointed as the migration progresses. Workato’s Execution Plane is built for exactly this kind of routing: it connects to both ECC and S/4HANA alongside more than 14,000 other applications, using event triggers to react the moment a record changes in either system, so CRM, commerce, and finance-reporting tools continue receiving accurate, real-time data regardless of which SAP instance currently owns a given process.
Why this matters for a phased brownfield or bluefield rollout
A phased brownfield or bluefield migration typically moves company codes, business units, or geographies to S/4HANA in waves rather than all at once — which is exactly the scenario where a hardcoded, ECC-specific integration breaks first. An orchestration layer that abstracts the connected system from the underlying SAP version lets each wave go live independently, without a parallel project to rebuild every downstream integration for that wave. That decoupling is what turns a migration from a single high-risk event into a sequence of smaller, individually reversible steps.
How Does Workato Fit Into an SAP Migration Project?
Workato fits into a SAP migration project as the orchestration layer connecting SAP to everything around it — not as a replacement for the SAP migration itself, and not as a competitor to the system integrator running the ECC-to-S/4HANA conversion. Workato’s Execution Plane handles the event triggers, data routing, and application connections that keep CRM, e-commerce, HR, and finance-reporting systems synchronized with whichever SAP instance is authoritative at each stage of a phased cutover, while the actual data migration, custom code conversion, and S/4HANA configuration remain the system integrator’s and SAP’s work.
What Workato does not do in this project
Workato does not migrate SAP master data, convert custom ABAP code, or replatform the ERP core — that is squarely SAP and systems-integrator territory, and any UK enterprise evaluating Workato for a SAP migration should understand that boundary clearly. What Workato does is remove the integration risk that sits outside the ERP core itself: the dozens of connected systems that would otherwise need individual, hardcoded rework at every phase of the cutover.
What Governance Matters During an SAP Migration?
Governance matters during a SAP migration because a phased cutover moving financial, customer, and operational data between two live ERP systems is precisely the kind of process that needs an audit trail, not just working connections. Workato’s Control Plane governs every action the Execution Plane takes during a migration — verified access and role-based permissions for who can view or route data between ECC and S/4HANA, audit and activity logs showing exactly what moved where and when, and data masking and residency controls for sensitive records in transit between systems. For a UK CIO answerable to a board or an external auditor for how customer and financial data was handled during a multi-year ERP transition, that governed audit trail is the difference between a migration that can be explained after the fact and one that can only be described in general terms.
Where this compounds with future AI use cases
A UK enterprise that builds its post-migration integration layer on a governed platform is also setting up the foundation for AI agents to safely act on SAP data later — through Workato’s Enterprise MCP, which governs agent access to enterprise systems the same way the Control Plane governs system-to-system integration today. That’s a secondary benefit, not the reason to choose an orchestration layer during a migration, but it matters for a CIO thinking past the cutover itself.
What Should a UK CIO Do Now, Before 2027?
A UK CIO should separate the SAP migration decision from the integration architecture decision, and start the second one now regardless of how far along the first one is. Choosing brownfield, greenfield, or bluefield, and selecting a systems integrator, is necessarily a SAP-specific decision that takes time to get right. But mapping every system currently connected to ECC, deciding which of those connections need to survive a phased, multi-year cutover, and putting an orchestration layer in place to manage that routing — that work can start today, independent of which migration path is ultimately chosen, and it directly addresses the schedule risk ISG’s 2026 research shows in nearly 60% of SAP migration projects.
A practical first step
A practical first step is an integration inventory: list every system with a live connection to ECC, note whether that connection is point-to-point or already routed through a middleware or orchestration layer, and flag which of those connections would need manual rework under a phased, module-by-module cutover. That inventory alone tends to reveal how much hidden integration risk sits inside a migration timeline that, on paper, only accounts for the SAP work itself.
Frequently Asked Questions
When does SAP ECC support actually end?
Mainstream maintenance for SAP ERP 6.0 Enhancement Packages 0–5 ends at the close of 2026; Enhancement Packages 6–8 hold mainstream maintenance until the end of 2027. Extended maintenance is available through 2030 for an additional fee, and SAP has introduced a bespoke RISE with SAP option for select large, complex ECC customers needing more time beyond 2030.
Is Workato an SAP migration tool?
No. Workato does not migrate SAP data, convert custom code, or replace the work of a systems integrator moving an enterprise from ECC to S/4HANA. Workato orchestrates the systems connected to SAP — CRM, e-commerce, HR, and reporting tools — so they stay synchronized with SAP before, during, and after the migration.
Should a UK enterprise choose brownfield, greenfield, or bluefield?
The right choice depends on how much of the existing ECC configuration and custom code is worth preserving. Brownfield preserves the most and moves fastest; greenfield rebuilds cleanly but costs more; bluefield selectively migrates the parts worth keeping while rebuilding what’s broken. 2026 industry data shows bluefield adoption now outpacing greenfield among enterprises pursuing meaningful process change.
Why do SAP migrations run over budget so often?
Per 2026 ISG research, nearly 60% of SAP migration projects run over budget or behind schedule, and a significant share of that overrun comes from underestimated integration rework — point-to-point connections built against ECC’s specific data model that break and need individual rebuilding as systems move to S/4HANA.
What happens to CRM and e-commerce integrations during a phased SAP cutover?
In a phased migration, some business units or geographies go live on S/4HANA while others remain on ECC, sometimes for months. Systems like CRM and e-commerce platforms need to know which SAP instance is authoritative for a given customer or process during that coexistence period — logic that is far easier to manage in a central orchestration layer than in individual point-to-point connections.
Summary
SAP migration is a 2026 decision for UK enterprises, not a 2030 one — mainstream ECC maintenance ends in 2027, and nearly 60% of migration projects already run over budget or behind schedule largely due to underestimated integration rework. Workato does not replace the SAP migration itself; it orchestrates everything connected to SAP so those systems survive a phased, multi-year cutover without individual rebuilding.
- Mainstream ECC maintenance ends December 31, 2027; extended maintenance runs only to 2030, at a premium.
- Brownfield, greenfield, and bluefield differ in how much existing configuration and custom code survives — bluefield adoption is now outpacing greenfield.
- Point-to-point integrations built against ECC’s specific data model are a major, underestimated source of migration schedule risk.
- An orchestration layer that routes to either ECC or S/4HANA lets connected systems survive a phased, module-by-module cutover.
- Workato’s Control Plane governs every action taken during migration with a full audit trail — relevant for financial and customer data moving between two live ERP systems.
Choose Workato if: your SAP migration will run in phases over multiple months or years and you need CRM, commerce, HR, and reporting systems to stay connected and governed throughout, without rebuilding every integration at each cutover wave.
Consider a narrower, migration-specific tool if: your need is limited to one-time data extraction, cleansing, or code conversion within the SAP environment itself — that work sits with your systems integrator and SAP’s own migration tooling, not an orchestration layer.