Preparing for SAP S/4HANA with the Readiness Check

Introduction

Migrating from SAP ECC to SAP S/4HANA is one of the most significant undertakings an organisation can face. The challenge is not just about executing a technical upgrade - it’s about ensuring business continuity, reducing risk, and identifying the correct opportunities for innovation and optimisation. 

One of the most powerful tools to prepare for this journey is the SAP Readiness Check. Far more than a technical report, it provides a structured, system-specific view of the changes, challenges, and opportunities ahead. 

What Is the SAP Readiness Check? 

The SAP Readiness Check is an SAP-delivered analysis that evaluates your SAP ECC system and highlights the factors that will affect your migration to SAP S/4HANA. Among these factors are the following critical pillars: 

1.  Simplification Items 

The tool highlights which processes, functions, or data models change under SAP S/4HANA. Each simplification item is categorised and effort-ranked from Low to High, providing early visibility into mandatory changes (such as Universal Journal or new Asset Accounting) and optional items that can deliver tangible value to your organisation. 

 2. Financial Data Quality 

It is often said that if you started your data cleansing and preparation activities yesterday you’d still have started too late! - Businesses often under-estimate the effort required to get their data ready for SAP S/4HANA. Conversion success depends on the consistency of General Ledger, Asset Accounting, and Material Ledger data. The Readiness Check provides heatmaps and categorised error lists, helping you quantify and prioritise remediation effort. 

 3. Customer Vendor Integration (CVI) 

Continuing the theme of data readiness, SAP S/4HANA requires customers, vendors, and contacts to be harmonised into the Business Partner model. This is one of the most significant data changes required; this analysis details record volumes, data quality issues, and required User Interface enhancements for custom fields – giving you clear insight into the task at hand. 

 4. Custom Code Analysis 

Remember all that customisation (Z Code) you were encouraged to build during your original SAP ECC implementation to make the system your own? Well now we need to make sure it will continue to function in the world of SAP S/4HANA – most will require adaptation and some may even be able to be removed! The Readiness Check identifies custom objects, categorises them by relevance, and provides information on SAP’s Quick Fix support for remediation. This ensures development teams can plan realistic timelines and avoid surprises late in the project...but first, make sure you ask if the coding is still even required!  

 5. Business Process Discovery & Innovation Potential 

Beyond remediation, the Readiness Check also analyses how your business processes currently run and identifies areas with optimisation potential. It looks at: 

• Automation levels in back-office processes (e.g. order creation, invoice posting). 

• Transactional backlog (open, overdue items that may need to be cleared before migration). 

• Non-standard processes that increase complexity and may be candidates for simplification. 

These collective insights not only inform migration scope but also highlight opportunities for process standardisation, automation, and adoption of SAP Fiori innovations. For programme leadership, this creates a direct link between the technical case for conversion and the business case for transformation and value creation – often one of the hardest questions to answer. 

By consolidating these checks, the Readiness Check transforms what could be a daunting discovery process into an actionable roadmap. 

Additional Insights

While the above pillars form the backbone of project scoping, the SAP Readiness Check also delivers valuable complementary analyses: 

• Add-On Compatibility – Identifies third-party and SAP add-ons that may block or complicate conversion. 

• Active Business Functions – Flags business functions that may not be compatible or need replacement. 

• Sizing & Data Volume – Provides projections of the HANA database footprint, helping scope infrastructure and licensing needs. 

• Planned Downtime Calculator – Offers initial guidance on likely downtime windows for conversion. 

• Interface/Integration Impact Analysis – Highlights integration points that could be affected by the conversion. 

• Recommended SAP Fiori Apps -Identifies the SAP Fiori applications (the primary user experience) that are relevant for your business.  

Together, these checks will provide you with a comprehensive risk and effort map for your transformation programme. 

Why the Readiness Check Matters to Programme Leadership

From a leadership perspective, the Readiness Check does three critical things: 

1. Sets the Scope Early 
   It provides an evidence-based view of what will change, what must be fixed, and what optional improvements can be planned. This clarity is vital when defining programme scope and budget. 
2. De-Risks the Project 
   Many system conversions stumble not because of poor execution, but because hidden inconsistencies or mandatory changes were overlooked. The Readiness Check surfaces these issues before they become blockers later in the project timeline. 
3. Aligns Business and IT 
   Some findings (such as mandatory process redesigns or data changes) require business input. Having these surfaced early allows Programme Managers to manage expectations early, engaging the right stakeholders at the right time and reduce the potential for later friction.

Turning Findings into Action 

The output of the Readiness Check can look technical, but when structured into workshops and decision points it becomes a strategic planning tool: 

• Group 1: Mandatory Remediation – Issues that must be addressed before conversion, such as activating new Asset Accounting or resolving General Ledger inconsistencies. These items are best tackled as pre-projects ahead of the main conversion/upgrade. 

• Group 2: Fit-to-Standard Workshops – Items that require business-led process redesign (e.g. SD Rebates replaced by Settlement Management). 

• Group 3: Non-Relevant or Optional Items – Simplification items that either don’t apply or can be deferred, but should still be noted for long-term roadmap planning.  

In practice, organisations will run a series of workshops to categorise findings and agree on pre-projects, remediation activities, or governance actions. This ensures the Readiness Check is not just a diagnostic tool, but serves as a building block for your entire programme. 

Beyond the Readiness Check 

While the Readiness Check is a cornerstone of the Discovery phase, its findings also feed into later stages of SAP Activate: 

• Prepare – Starting pre-projects and remediation. 

• Explore – Using Fit-to-Standard workshops to validate business process alignment. 

• Realise & Deploy – Executing conversion activities with confidence that risks have been addressed. 
  

Key Takeaways 

• The SAP Readiness Check is not optional - it is a vital tool for scoping, risk management, and stakeholder alignment in a SAP ECC to SAP S/4HANA upgrade. 

• Its critical analyses (e.g. Simplification Items, Compatibility Scope, Financial Data Quality, CVI, Custom Code checks, etc…) highlight both mandatory and strategic opportunities and provide the backbone for your programme plan. 

• Interpreting results through structured workshops enables leadership to make informed decisions on pre-projects, programme design, and governance. 

• Running the Readiness Check early ensures your programme is built on facts, not assumptions, and provides the clarity needed for successful execution. 

At Rapid X, we have extensive experience guiding organisations through this critical stage. By combining SAP’s Readiness Check results with our proven expertise, we can turn your outputs into actionable roadmaps - aligning technical, business, and governance workstreams for a smooth and low-risk upgrade.