You need to determine whether you're shooting for a Transformation or a Technical upgrade. This is your foundation, and such a decision will have a huge bearing on cost, outcomes and the potential ROI. Aligning on a shared transformation vision sets the tone for everything that follows - from scope and resourcing to timelines and success metrics. It forces your leadership to ask: 'Why do we need to change?', 'What does the future of ERP look like in our organisation?', 'How will we accomplish that?' Answering these questions helps the organisation imagine a different future. This vision should be documented and tested against organisational strategy.

For example, if strategy dictates that the business is to simplify and modernise its processes you’re not going to want to pass up this opportunity to evaluate new ways of working and determining how a move to SAP S/4HANA can support that. Making this vision explicit early avoids disagreements and helps focus decision-making across the programme.

Useful inputs into the vision can be borne from a Business Capability Model - This helps visualise what the business does today and what it needs to do tomorrow. You can download our example Business Capability Model Framework here to get started. 

Your path to SAP S/4HANA determines the DNA of your programme. The choice should be heavily influenced by your vision and organisational strategy (as just discussed) as well as technical factors such as existing levels of customisation (custom code), data quality, appetite for risk and ambition to change – but it all boils down to one of three core options: Brownfield, Greenfield, or something in between?  Selecting the right path from SAP ECC to SAP S/4HANA is one of the most significant decisions you'll make. It affects cost, complexity, risk, licensing, and organisational change impact.  

Many organisations may default to a Brownfield (technical conversion) approach, driven by a need to stay in support, and a ‘JFDI’ attitude without really assessing whether a transformation-led path would deliver greater long-term value. 

A good Phase Zero should evaluate the benefits, risks, and constraints of all approaches: 

• Brownfield (System Conversion) – primarily a technical upgrade, preserving existing ways of working (processes), configuration and data. Typically, this will be the quickest route to SAP S/4HANA.  

• Greenfield (New Implementation) – a clean-slate approach with standardised processes, requiring data migration and a significant change management exercise. Usually more costly, but could deliver the largest ROI.  

• Selective Data Transition (Hybrid) – Takes forward the best (differentiating) aspects of your existing solution and integrates with a selective set of new SAP S/4HANA processes/capabilities.  This is a good middle ground, allowing for innovation whilst balancing overall implementation costs. 

You can see a full breakdown of the approaches in our guide: SAP S/4HANA Deployment Options Explained (which Path fits your organisation).

There are many required inputs into this decision, including organisation goals/strategy, desired outcomes, budget (!) etc…To get a head-start on the potential impact (including potential benefits) we recommend running the SAP Readiness Check as soon as possible. Ensure you seek the right guidance in evaluating the outputs of this report, involving the right teams and experts within your own (or a 3rd party) organisation. Of all the decisions to make, the transformation/upgrade approach is one of the most critical as it sets the technical foundation for the programme and has a significant impact on costs and project timeline.  

Given the complexity of the journey to SAP S/4HANA it is unlikely you will have the in-house expertise and/or capacity to undertake such a programme on your own. Even if you have an incumbent service provider who ‘could’ deliver such a programme, you should consider they will likely need to involve different staff to those who support you day-to-day. Your SI will shape how the programme is delivered - from solution design and timelines to team dynamics and risk management. Therefore, selecting the right SI is a critical step in de-risking your transformation. This decision directly influences how the programme is planned, governed, and experienced by your business. A strong partner brings delivery assurance, accelerators, and industry insight. The wrong one can create a rigid, reactive delivery model, over-customise the solution, and erode business confidence. 

Getting this right ensures clarity on scope, cost, and ways of working. It also validates the assumptions in your business case and allows you to contract based on value, not just price. As mentioned before, selecting the wrong partner can be one of the main factors that causes your programme to derail. Dedicate the time in Phase zero to run a structured SI selection process, using clear evaluation criteria and collaborative working sessions to see how the SI engages with you, your people and priorities. You will potentially be working together for the next 12 – 48+ months, so cultural alignment will be key in helping you to achieve your business goals and desired outcomes.  

Tip: Ensure through the SI selection proposal and resulting SoW that you understand the differing roles and responsibilities across the programme through the use of a RASCI. This will help ensure a fair comparison of SI responses and guard against Change Requests later on. See our related guide: The importance of a RASCI for ERP Transformation Projects. 

When starting your journey to the latest iteration of SAP, defining your target architecture early is critical. It shapes not just the technical environment, but also the licensing model, commercial structure (CapEx vs OpEx), innovation potential, integration strategy, and your organisation’s ability to scale and evolve. These are not just IT decisions - they directly impact ROI, programme risk, and future business agility! 

SAP now refers to its modern ERP portfolio as SAP Cloud ERP, and navigating its options can be complex. Organisations must make two foundational choices: 

• How will we license SAP Cloud ERP in the future?  - Subscription (OpEx) or Perpetual (CapEx/Bring Your Own Licence) 

• How will we host and operate our SAP Cloud ERP instance? - On-premise, third-party/hyperscaler, or SAP-managed cloud 

There are multiple deployment options, each with specific architectural, commercial, and operational characteristics. This decision is further complicated by recent changes to product names and licensing options. Below we will take you through the key options, but you can see full details in our guide: SAP S4HANA Target Architectures and Licensing Models What You Need to Know.

1. SAP Cloud ERP, Private Edition - Designed for customers seeking the power of cloud, but still wanting a layer of control and flexibility over customisations – potentially due to retain their own differentiating processes/customisations, or where there are specific security considerations etc.  
2. SAP Cloud ERP, Tailored Edition - The classic ‘on-premise’ experience deployed in your own Data Centre or chosen Hyperscaler, fully customer-managed. This will most likely be the go-to model for customers with large, complex solutions. 
3. SAP Cloud ERP, Public Edition - True SaaS approach. Fixed scope, rapid deployment, regular innovations. Not suitable for customers with extensive customisations, security constraints those or who want an additional level of control over their ERP landscape. Ideal for net-new SAP customers or subsidiaries seeking fast innovation and standardisation. 

Your architectural decisions must align with your transformation vision, programme budget, and internal capabilities. This is not just a technical decision! Key considerations include: 

• Cost Structure: CapEx vs OpEx, upgrade timelines, and support duration 

• Security & Compliance: Who owns what? Who manages what? 

• Innovation & Integration: Flexibility to adopt new capabilities and integrate with emerging platforms 

• Maintainability & Future-proofing: How often will you upgrade? Who will manage those upgrades? 

• Licensing & Contracting: Impact on SI scope, business case, and long-term TCO 

Finalising your target model is a foundational outcome of Phase Zero - and not doing so invites commercial ambiguity (read additional costs!), programme misalignment, and avoidable delays in later stages. 

Probably one of the most challenging aspects of Phase Zero is being able to define the ‘why’ for your transformation and quantify what success looks like – beyond just supportability or compliance. 

Too often, SAP transformation business cases focus on technical necessity - staying in support or reducing risk - without fully exploring or validating the potential for value creation. A compelling and credible business case must be rooted in your transformation vision and reflect the outcomes that truly matter to your organisation. 

If your vision is primarily Risk Mitigation, your value case may focus on: 

• Enhanced security and business continuity 

• Improved compliance and audit-readiness 

If your vision is one of transformation, the business case should explore: 

• Revenue / Value Impact e.g. improving the customer experience or streamlining order entry 

• Cost-efficiency e.g reducing time to market for new products 

• Enabling new business models e.g. Direct to Consumer channels 

• Unlocking innovation e.g. AI, Carbon accounting 

To make the business case real, not just aspirational, we recommend a structured, collaborative approach as part of the Phase Zero approach – this is described in full in our Transformation Business Case essentials page, which covers what a Business Case is, the key elements, challenges and how to get started. 

By taking a structured approach, organisations can build a realistic and accountable business case that forms the foundation of your programme.