Migrate to S/4HANA without the risk

The 2027 SAP ECC end-of-mainstream-maintenance deadline is fixed. Organisations that migrate on a planned timeline control the outcome. Those that wait face compressed timelines, premium partner rates, and the operational risk of a rushed cutover. BCS delivers SAP S/4HANA migrations that preserve business continuity while retiring the technical debt that has been holding the roadmap hostage.

30-minute discovery session.

ECC Mainstream Exit
2027

SAP ends mainstream ECC maintenance in December 2027, with extended support to 2030 (SAP).

S/4 Programmes Carry Mods
Most

Majority of S/4HANA migrations carry ABAP modifications that constrain clean-core upgrade adoption (Gartner).

Migrations Slip on Quality
Most

Majority of S/4HANA migrations face schedule slippage from custom code or data quality issues (Gartner).

Migration Approaches

Which migration path fits the landscape?

The right approach depends on the state of the ECC landscape, the volume of customisation, and how much of the current process model should be preserved versus redesigned. BCS delivers both, with the same clean-core discipline and assessment rigour applied regardless of the path chosen.

Every BCS migration starts with a structured assessment: actual custom code object count, data quality profile, integration inventory, and a timed cutover simulation. Scope is priced on evidence, not market benchmarks. Whether the programme follows a brownfield system conversion or a selective data migration, the outcome is the same — a clean-core S/4HANA system with technical debt permanently retired and Symphony automation live from go-live.

SAP ECC SOURCE LANDSCAPE ECC Finance FI · CO · Asset Acc ECC Operations MM · SD · PP Custom Code Z-objects · Exits BCS MIGRATION PROGRAMME Assess · Remediate · Deploy PATH A Brownfield PATH B Selective OUTCOME Clean Core Every path arrives at the same clean-core S/4HANA target Assessment-first · Technical debt retired · Symphony at go-live S/4HANA Finance Universal Journal · Live S/4HANA Ops Simplified · Automated BTP Extensions Differentiators · Retained SAP S/4HANA TARGET PLATFORM
Why S/4HANA Migrations Fail

The failure modes that turn migrations into crises

SAP S/4HANA migrations are among the most technically and operationally complex programmes in enterprise IT. The failure modes are well documented and largely consistent across organisations. What distinguishes the programmes that land from those that do not is whether these patterns were addressed before technical execution began.

× Industry norm What usually happens
✓ BCS approach How BCS prevents it
×
Custom code discovered late
A custom code impact assessment was skipped or deferred, leaving hundreds of Z-programs and exits to be assessed during the Realize phase under time pressure.
Custom code impact assessed and roadmapped before the programme starts
BCS runs a full ABAP custom code scan and impact analysis during Discover. Retirement, keep, and recode decisions are made before the migration approach is set, so the programme budget is based on evidence.
×
Data quality not addressed upfront
The migration assumed clean source data. Data quality issues surfaced during mock migration runs, forcing scope reductions and rushed remediation.
Parallel data quality programme from Prepare phase
Data profiling, cleansing, and deKorvai validation run as a parallel workstream from day one. Migration objects are loaded against clean data, not data that teams intend to fix during the cutover window.
×
Integration mapping incomplete
Third-party and satellite system integrations were not fully mapped before the migration began, creating integration gaps discovered only during system integration testing.
Full integration inventory and regression test plan confirmed upfront
Every integration touchpoint is catalogued, the regression test scope is agreed, and integration testing is scheduled as a first-class workstream, not discovered as an afterthought in User Acceptance Testing.
×
Cutover window underestimated
The technical cutover sequence was built for the ideal scenario. Fallback procedures, parallel run requirements, and reconciliation time were not factored into the window.
Cutover plan rehearsed and timed before go-live weekend
BCS cutover plans are built at task level with owners, time buffers, and defined rollback triggers. Dress rehearsals are completed twice before the final weekend so every step is understood in advance.
×
Business continuity not planned
Operational teams were not prepared for system downtime. Manual fallback procedures were absent or untested, creating business disruption during the cutover window.
Zero-defect cutover with pre-built reconciliation tools
Pre-built reconciliation tooling verifies financial balances, open item counts, and stock positions before the business is live on the new system. Go-live is confirmed by reconciled data, not by assumption.
×
Post-migration stabilisation ignored
The hypercare period was treated as informal support. Regression issues, performance degradation, and adoption gaps accumulated without a structured resolution programme.
Structured post-migration stabilisation with Symphony from day one
A defined hypercare programme keeps the landscape stable post-migration while Symphony agents absorb transactional volumes that would otherwise require emergency manual intervention during the stabilisation period.
Business Outcomes

What the board gets from a successful S/4HANA migration

Migrating to S/4HANA is the most consequential SAP investment an organisation will make this decade. The business case is not just about keeping the lights on beyond 2027. It is about the new operating model that sits on the other side of the migration window.

A future-proof platform before the 2027 deadline

SAP ECC mainstream maintenance ends in 2027. Organisations that migrate on a planned schedule avoid extended maintenance premiums, constrained partner availability, and the operational risk of a deadline-driven migration.

Real-time operational visibility

The Universal Journal, embedded analytics, and live MRP replace the batch-heavy, report-intensive operations model of ECC. Decisions are made on current data, not last night's extract.

Technical debt retired permanently

An average BCS migration retires 55% of the legacy custom code base, eliminating the upgrade friction, security risk, and maintenance cost that has accumulated over the ECC lifetime.

SAP S/4HANA migration outcomes and risk managed transition

Compliance rebuilt on a modern foundation

Anugal embeds continuous controls monitoring into the new S/4HANA system from cutover, replacing the manual compliance processes built around ECC limitations.

Roadmap unlocked

A clean-core S/4HANA system accepts every future SAP innovation, AI, embedded automation, industry cloud, without re-implementation. The migration pays forward for a decade.

Operational efficiency from day one

Symphony agents are deployed at cutover to absorb routine workloads in the new system. Stabilisation is supported by automation, not headcount spikes.

Methodology

How does BCS deliver an S/4HANA migration?

Migration is a high-risk programme on a fixed deadline. BCS structures every S/4HANA migration as six phases where the custom code, data quality, and process simplification decisions in the first three phases determine whether the cutover window holds. Everything after that is execution.

01
Phase 1

Migration Assessment

BCS profiles the custom code, data quality, integration landscape, and cut-over complexity using SAP Readiness Check alongside BCS analysis tooling. Migration risk is quantified before scope and price are committed.

02
Phase 2

Architecture and Design

The target S/4HANA architecture, clean-core extension design, integration re-architecture, and migration path (brownfield, bluefield, or greenfield) are confirmed. Every decision is anchored to the Readiness Check findings, not vendor assumptions.

03
Phase 3

Data Quality Programme

Legacy data is profiled, cleansed, deduplicated, and enriched as a parallel workstream before the migration window opens. Data quality is treated as a programme gate, not an assumption that can be revisited later.

04
Phase 4

Technical Migration

SUM with DMO runs the brownfield system conversion, or LTMC orchestrates selective data migration. Custom code is remediated, configuration transferred, and Universal Journal activated in the new platform.

05
Phase 5

Testing and Cutover Rehearsal

End-to-end regression, integration, and performance testing run in sequence. Multiple full-cycle cut-over rehearsals validate the production timeline with measured durations and fallback decision points.

06
Phase 6

Go-Live and Hypercare

Production cut-over runs with reconciliation sign-off, structured hypercare, and severity SLAs. Symphony agents absorb the L1/L2 peak that follows every major migration, freeing BCS architects for complex problem management.

Core Capabilities

Migration expertise across every S/4HANA workstream

BCS migration practice covers every technical and functional dimension of a complex S/4HANA programme, from custom code remediation and data quality through integration cutover and the Symphony-augmented operating model that is live on day one. Every capability below is a scoped workstream with defined deliverables, not a background task.

Custom Code Assessment & Remediation

Automated custom code impact analysis using SAP's Custom Code Migration app and BCS tooling. Every Z-program, enhancement spot, BAdi implementation, and implicit enhancement assessed and classified, retire, refactor as BTP extension, or carry forward under clean-core rules.

Data Migration Programme

LTMC, LTMOM, and custom migration object design. Legacy data quality programme, migration cockpit configuration, and reconciliation reports that sign off each load.

Universal Journal Migration

FI, CO, and Asset Accounting migration to the Universal Journal. Period carry-forwards, open item transfers, and balance validation against the legacy system.

Integration Re-architecture

Third-party and satellite system integration re-routing to the new S/4HANA APIs. PO to CPI migration where applicable, BCS holds full CPI implementation capability.

Embedded Analytics Activation

CDS views, SAP Analytics Cloud connectivity, and Fiori analytical apps activated on the new platform. Reporting modernised as part of the migration, not deferred.

Cutover Planning & Execution

Technical cutover sequence, fallback decision criteria, parallel run architecture, and reconciliation scripts. Multiple dress rehearsals with measured window durations before production cutover.

S/4HANA Brownfield Conversion

System conversion using SUM with DBACOCKPIT optimisation. Downtime minimisation, custom transport import sequencing, and post-conversion activation of S/4HANA simplifications.

SAP Fiori Activation

Fiori launchpad configuration, tile setup, and role-based UX activation across migrated business processes. UX improvement delivered as part of the migration programme.

Post-Migration Hypercare

Structured hypercare with daily triage, severity SLAs, performance monitoring, and Symphony-augmented L1/L2 resolution. Stabilisation designed as a programme phase, not an informal period.

The BCS Difference

What other SAP migration partners cannot offer

Most migration partners deliver a new system. BCS delivers a new operating model alongside it. Symphony, deKorvai, and Anugal are scoped during migration design and deployed at cutover, so the business operates at a higher baseline from day one rather than waiting for a follow-on programme that may never arrive.

Agentic Operations Platform

Symphony

Symphony agents are deployed at migration cutover, autonomously absorbing the operational workload in the new S/4HANA environment from the first production day. Approvals, exceptions, and period-end tasks that previously required manual handling run without human triage, reducing the hypercare staffing burden migrations typically generate.

  • Deployed at cutover to absorb operational workload immediately
  • Autonomous exception handling in the new S/4HANA environment
  • Period-end close automation active from first close post-migration
  • Support ticket deflection at L1/L2 during hypercare
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AI Decision Intelligence

deKorvai

The data that arrives in S/4HANA after migration is cleaner and better structured than anything in ECC. deKorvai is built to extract intelligence from it immediately, turning the migration into the starting point for predictive operations rather than just a platform change.

  • Post-migration anomaly detection across migrated transaction history
  • Demand and inventory signal sensing active from go-live
  • Predictive analytics replacing the ECC batch reports retired by migration
  • Cash flow forecasting on the Universal Journal from day one
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Compliance & Controls Automation

Anugal

Migration is the right moment to reset the compliance posture. BCS deploys Anugal at cutover to monitor SoD compliance against the new S/4HANA role design, collect audit evidence from the first period, and eliminate the access control gaps that accumulate silently across long-running ECC landscapes.

  • Continuous SoD monitoring from cutover, not quarterly reviews
  • Automated audit evidence collection in the new S/4HANA system
  • Access risk analytics applied to the post-migration role design
  • Compliance reporting rebuilt on S/4HANA from the first period
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Frequently Asked Questions

Refer to this section for answers to frequently asked questions related to SAP S/4HANA migration.

What is the difference between brownfield, bluefield, and greenfield migration?

Brownfield converts an existing ECC system to S/4HANA in place, retaining data, configuration, and most custom code. Bluefield (selective data transition) builds a new S/4HANA system and selectively brings forward data and processes. Greenfield is a fresh implementation. BCS recommends after impact analysis, not before.

How long does an S/4HANA migration typically take?

Brownfield conversions on a mid-size landscape typically run 9-15 months. Bluefield runs 12-18 months. Greenfield enterprise implementations run 15-24 months. The custom code footprint, data volume, integration complexity, and number of legal entities are the dominant timeline drivers.

What happens to existing custom ABAP code (Z-programs) during migration?

Every Z-program, BAdi, user exit, and enhancement is classified by SAP Custom Code Migration app and BCS analysis: retire (no longer needed), refactor (move to BTP extension), or carry forward (true clean-core compliant). Typical BCS migrations retire or refactor 40-55% of legacy custom code.

Does the 2027 ECC deadline mean migration must finish by 2027?

SAP mainstream ECC maintenance ends December 2027. Extended maintenance is available to 2030 at premium cost. Programmes starting in 2026 retain a viable transformation window. Starting in 2027 compresses scope, pushes into premium partner rates, and increases re-implementation risk.

Can the cutover happen over a single weekend?

Yes for most mid-market landscapes (typically 36-72 hour cutover windows). Enterprise landscapes with high data volumes and many integrations may require a multi-stage cutover with phased migration of legal entities or business units. Cutover duration is validated through full-cycle rehearsals before the production window is confirmed.
Why BCS

What makes BCS different for S/4HANA migrations?

12 years of SAP delivery across 40+ enterprise programmes, including brownfield conversions, selective data migrations, and multi-entity cutover programmes, is what sits behind BCS migration methodology. That experience is why the approach is built around prevention rather than crisis management.

Assessment before execution, always

BCS runs a structured migration assessment before any technical work begins. Custom code volume, data quality state, integration complexity, and cutover risk are quantified before the project is scoped and priced.

Data quality is a gate, not a task

Data migration is the most common cause of migration delays and post-go-live defects. BCS runs a parallel data quality programme from the start of the project, data is clean before the migration begins.

Custom code retirement is an outcome

Most partners migrate custom code. BCS retires it. An average 55% of legacy custom objects are replaced with standard S/4HANA functionality or refactored as clean-core BTP extensions, permanently eliminating future upgrade friction.

Cutover rehearsed, not assumed

Multiple full-cycle cutover rehearsals with measured durations, fallback decision checkpoints, and reconciliation sign-off before production cutover. The cutover window is a known quantity, not a projection.

Automation covers the stabilisation peak

Symphony agents are deployed at cutover. The L1/L2 support load that peaks in the first 90 days post-migration is absorbed by automation, protecting the business from the operational disruption that typically follows a major system change.

Migration scope is priced on evidence, not benchmarks

BCS scopes and prices migrations from a structured assessment: actual custom code object count, measured data volumes, documented integration endpoints, and a timed cutover simulation. Organisations do not receive a budget estimate built on industry averages that later requires significant revision.

Get Started

Start the S/4HANA migration on the right timeline

The 2027 ECC maintenance deadline is fixed. The organisations that migrate on a planned programme control the outcome. Tell BCS where the programme stands and BCS will scope a migration programme that eliminates the risk and delivers the S/4HANA foundation the long-term roadmap requires.

30-minute discovery session.