The 2027 SAP ECC end-of-mainstream-maintenance deadline is no longer a distant calendar entry. It is a hard constraint. And the window for securing a qualified SAP S/4HANA implementation partner who can actually deliver is narrowing fast.

According to Gartner (2024), over 60% of ECC customers will still be mid-migration or pre-migration by 2027 - meaning the race for experienced S/4HANA consultants has already begun. The CIOs who will come out of this cycle on budget and on strategy are not the ones who moved fastest. They are the ones who asked the right questions.

This guide gives you seven of them.

Why Generic Partner Vetting No Longer Works

Most vendor evaluation frameworks were written in a different era. They ask about team size, hourly rates, and reference customers. Those questions are not wrong - they are simply insufficient for a migration that must deliver a system ready for SAP Business AI, not just a functioning ERP.

The real risk in 2026 is not choosing a bad partner. It is choosing a competent-but-backward-looking one: a firm that migrates your existing landscape cleanly but recreates legacy architecture in S/4HANA, blocking the AI capabilities your business strategy now depends on.

According to an SAP survey (2024), 87% of global executives agree AI is essential to their business strategy. That figure reshapes what "a successful migration" means. A partner who hands you a live S/4HANA system that cannot consume Joule, embedded analytics, or SAP's AI services has not completed the job.

The seven questions below are built for this reality. Each one is designed to surface where a partner's capability ends - before you sign an SOW.

Question 1: How Do You Enforce a "Clean Core" Strategy During Migration?

Bottom line: If the partner cannot articulate a specific methodology for reducing custom code and enforcing clean core principles, the migration will recreate the problem you already have.

The clean core concept is not a preference - it is an architectural prerequisite for the direction SAP is taking its platform. An S/4HANA system loaded with custom modifications in the core becomes expensive to maintain, slow to update, and structurally unable to absorb SAP's quarterly innovations and AI enhancements.

According to ASUG and LeanIX research (2024), 85% of organizations name clean core adoption as a top priority for their S/4HANA migration. Despite that, many implementation partners still treat custom code as a given, migrating whatever the customer has always had.

A qualified partner will walk you through how they classify custom code, what they recommend moving to SAP BTP extensions versus eliminating entirely, and how they govern scope creep that reintroduces customization during the project. Ask them to show you the decision framework, not just describe it.

What a strong answer looks like: The partner references a formal clean core methodology, explains the ABAP Cloud model and extensibility framework, and can show examples of custom code reduction ratios from prior engagements.

What a weak answer looks like: "We'll assess your custom code early in the project." That is not a strategy. That is a delay.

Question 2: What Is Your Approach to Automated Custom Code Remediation?

Bottom line: Manual code review at enterprise scale is not viable. If a partner's custom code remediation answer is "our team will review it," the project timeline and budget will expand accordingly.

Enterprise ECC landscapes typically carry thousands of custom ABAP objects accumulated over decades. Reviewing, remediating, and reclassifying that code manually is the single largest hidden cost driver in S/4HANA migrations. Partners who rely primarily on manual review either underquote the effort or underdeliver on scope.

The differentiator in 2026 is tooling. Partners with mature automated code analysis capabilities - using SAP's own tools like the Custom Code Migration App and ABAP Test Cockpit, or validated third-party equivalents - can analyze an entire custom code landscape in days, not weeks. That analysis becomes the foundation for a clean core roadmap that is grounded in data, not estimation.

The right question is not whether they use tools. It is which tools, how deeply those tools integrate into the migration methodology, and how the output maps to the partner's clean core enforcement plan from Question 1.

What a strong answer looks like: A named toolset, an explanation of how automated findings feed into the migration design, and a documented process for handling objects that cannot be automatically remediated.

What a weak answer looks like: "We have experienced ABAP developers who will handle that." Experience is not a methodology.

Question 3: How Do You Align the Migration with RISE with SAP and BTP?

Bottom line: A partner who treats RISE with SAP as a procurement question - rather than an architectural one - is not thinking about your post-migration operating model.

RISE with SAP is SAP's bundled cloud transformation offering, combining S/4HANA Cloud Private Edition with managed services, cloud infrastructure, and access to the SAP Business Network. For many organizations, RISE is a viable path to reducing infrastructure complexity and accessing SAP's roadmap innovations faster.

But RISE is not simply a licensing structure. It has architectural implications for how the system is configured, how extensions are built (always on BTP, never in the core), and how the organization accesses updates on a predictable cadence. A partner who has not delivered RISE engagements will be learning on your project.

SAP Business Technology Platform is the adjacent question. BTP is where side-by-side extensions, integration scenarios, and AI services live in a clean core model. A partner who defaults to on-premise thinking - building extensions inside the S/4HANA core because it is faster - will create technical debt from day one and block your BTP adoption roadmap.

Ask specifically about BTP integration architecture. If the answer is vague, that is meaningful data.

What a strong answer looks like: The partner distinguishes RISE licensing tiers, explains when Private Edition versus Public Cloud is appropriate, and describes their BTP center-of-excellence model or equivalent.

What a weak answer looks like: "We support RISE with SAP." That is a marketing statement, not an architecture position.

Question 4: Can You Prove AI Readiness in the S/4HANA Architecture?

Bottom line: Migrating to S/4HANA and being ready for SAP Business AI are not the same outcome. Ask for proof that the partner architects for AI consumption, not just system functionality.

SAP's AI strategy is embedded in the product, not bolted on. Joule, SAP's generative AI copilot, requires specific S/4HANA configuration, data quality standards, and integration architecture to function. The same is true of SAP's embedded analytics, predictive capabilities, and the AI scenarios surfaced through SAP Build and BTP AI services.

A migration that delivers a technically sound S/4HANA system but ignores these readiness conditions will require a second engagement to close the gap. That second engagement is a cost that does not appear in the original SOW.

Ask the partner to walk you through their AI readiness checklist. It should include data quality standards, the extensibility model they enforce, how they configure S/4HANA to expose AI-ready APIs, and how they document AI activation steps in the post-go-live plan.

What a strong answer looks like: A documented AI readiness framework that covers data governance, Joule configuration prerequisites, and BTP AI service integration. References to specific customers who have activated SAP AI features post-migration are a strong signal.

What a weak answer looks like: "SAP S/4HANA has AI built in." Yes - but that is not the same as your system being configured to use it.

Question 5: What Does Your Post-Go-Live SAP AMS Framework Look Like?

Bottom line: Go-live is not the finish line. A partner without a structured Application Management Services model will leave your team to manage a system they may not yet fully understand.

S/4HANA migrations that fail do not always fail at cutover. Many fail in the 90 days after go-live, when the complexity of a new system collides with an operations team that has not yet built institutional knowledge. Without a defined support model, incidents that should take hours to resolve stretch into days, and process gaps that should have been caught in hypercare become embedded problems.

As an SAP Gold Partner, ITChamps delivers end-to-end S/4HANA services spanning advisory, migration, and ongoing SAP AMS. The distinction matters: a partner whose AMS practice is a separate team with no connection to the implementation team creates continuity gaps. The team that built the system should have a defined handoff process to the team that supports it.

Ask specifically about the hypercare period: how it is structured, how long it runs, what SLAs govern incident response, and how it transitions to steady-state AMS. Ask about the ratio of junior to senior consultants in the AMS model - this is where partners quietly shift margins.

What a strong answer looks like: A named AMS framework with defined SLA tiers, a documented hypercare process, a named escalation path, and evidence of AMS engagements that originated from prior S/4HANA migrations at the firm.

What a weak answer looks like: "We provide post-go-live support." That is a promise, not a framework.

Question 6: How Do You Structure Fixed-Price vs. T&M Engagements to Protect Our Budget?

Bottom line: Time-and-materials contracts in S/4HANA migrations are risk-transfer mechanisms. Understand what you are accepting before you sign.

Cost overruns are the most cited failure mode in enterprise ERP migrations. They are rarely caused by a single decision. They accumulate from scope changes, underestimated integration complexity, custom code surprises, and delayed business decisions that extend project timelines. The contract structure determines who absorbs those costs.

Time-and-materials engagements place most of the risk on the customer. Every scope change, every delay, every surprise in the landscape adds to the bill. Fixed-price engagements transfer risk to the partner - but only if the scope is defined precisely enough for a fixed price to be meaningful. A fixed-price contract on a loosely scoped migration is not protection; it is a ceiling that the partner will hit and then renegotiate.

The right question is not "do you offer fixed-price?" It is: "At what point in the engagement do you have enough landscape knowledge to commit to a fixed-price scope, and what discovery process gets you there?"

ITChamps leverages its proprietary 3PS framework to accelerate S/4HANA migration timelines while ensuring a strict clean core, including a scoping methodology designed to reduce ambiguity before commercial terms are finalized. That specificity is what makes a commercial model protective rather than notional.

What a strong answer looks like: A partner who describes a phased approach - a defined discovery or assessment phase that produces enough landscape documentation to support a credible fixed-price proposal - and who can articulate how change orders are governed.

What a weak answer looks like: "We can do fixed-price or T&M depending on your preference." That is not a risk management position. It is a sales position.

Question 7: What Are the Realistic Timelines and Resource Constraints for 2026?

Bottom line: Any partner who gives you a migration timeline in the first conversation without qualifying it against your landscape complexity and their current resource availability is telling you what you want to hear.

The consultant bottleneck is real. With the 2027 deadline forcing a compression of multi-year migration backlogs into 18 months of available capacity, experienced S/4HANA architects and project managers are already committed. Partners who are booking 2026 capacity now will have better teams available than those who begin staffing in Q3.

Migration timelines vary significantly based on landscape complexity, customization volume, data quality, organizational change management readiness, and integration scope. A greenfield S/4HANA implementation and a brownfield migration from a heavily customized ECC 6.0 system have almost nothing in common in terms of duration or resource requirements. Any estimate that does not account for your specific landscape is not an estimate - it is a placeholder.

Ask the partner to walk through their resource model for your engagement specifically: who the lead architect would be, whether that person is currently available for 2026 work, what the escalation path looks like if key resources change mid-project, and how they manage subcontractor dependency.

What a strong answer looks like: A transparent conversation about current capacity, named senior resources available for 2026 starts, a realistic milestone framework tied to your landscape complexity, and a clear statement that timelines will be confirmed after a formal readiness assessment.

What a weak answer looks like: "We can typically deliver in 12-18 months." Typically is not a project plan.

The Question Behind the Questions

Every question above is asking a version of the same thing: is this partner building toward your future, or managing their own risk in the present?

The 2027 deadline has created a market condition where many vendors can credibly promise an ECC-to-S/4HANA migration. Fewer can deliver one that leaves you with a clean, AI-ready architecture and a post-go-live support model that does not leave your team exposed.

The vetting process is the first test of a partner's rigor. How they answer these questions tells you more about their actual methodology than any reference call will.

Frequently Asked Questions

What is the SAP ECC 2027 deadline, and what happens if we miss it?

SAP will end mainstream maintenance for SAP ERP (ECC) on December 31, 2027. After that date, customers who have not migrated to SAP S/4HANA will need to purchase extended maintenance agreements, which carry additional cost and limit access to new functionality and SAP's evolving AI capabilities. The risk of delaying migration past 2027 is not just financial - it is operational, as the gap between ECC and the innovations available on S/4HANA will continue to widen.

What is a "clean core" in SAP S/4HANA, and why does it matter for AI?

A clean core means keeping the S/4HANA system as close to the standard SAP codebase as possible, with customizations built in the extensibility layer - typically on SAP BTP - rather than inside the core application. This matters for AI because SAP's embedded AI capabilities, including Joule and predictive analytics, are built to function on standard configurations. A heavily modified core creates compatibility conflicts that either block AI adoption or require costly remediation before AI features can be activated.

What is the difference between a greenfield and brownfield S/4HANA migration?

A greenfield migration builds a new S/4HANA system from scratch, without carrying over the existing ECC configuration and data. It is a higher-effort, higher-cost approach but offers the cleanest starting point for a modern architecture. A brownfield migration converts the existing ECC system in place, preserving existing configurations and data but also carrying over any existing technical debt. A third path - selective data transition - allows organizations to migrate specific processes or business units selectively. The right approach depends on the organization's technical landscape, timeline, and appetite for business transformation alongside the migration.

How do we evaluate an SAP implementation partner if we have limited internal SAP expertise?

Start with an independent S/4HANA readiness assessment before entering the partner selection process. A readiness assessment maps your current ECC landscape - custom code volume, integration complexity, data quality, and business process gaps - and produces the documentation a partner needs to give you a credible scope and timeline. Without that baseline, you are evaluating partners without the information needed to hold their proposals to account. ITChamps offers an S/4HANA Readiness Assessment as a scoped, time-bound engagement designed to produce that baseline before an implementation partner is selected or contracted.

What is RISE with SAP, and should we pursue it?

RISE with SAP is SAP's business transformation-as-a-service offering. It bundles S/4HANA Cloud (Private or Public Edition), cloud infrastructure, SAP Business Network access, and tools for business process intelligence into a single subscription. Whether RISE is the right commercial model depends on your organization's preference for managed infrastructure, your existing cloud agreements, and your migration timeline. RISE is not inherently better or worse than a traditional license model - it is a different operating model with specific architectural implications that your implementation partner should be able to evaluate against your requirements.

Book an ITChamps S/4HANA Readiness Assessment. Before selecting a partner, know your landscape. Don't leave your 2027 migration to chance - contact ITChamps to schedule your readiness assessment and build a partner evaluation framework grounded in your actual system complexity.

Book Your S/4HANA Readiness Assessment →

Footer Disclosures

SAP, SAP S/4HANA, SAP ECC, RISE with SAP, SAP Business Technology Platform, SAP BTP, Joule, and other SAP products and services mentioned herein as well as their respective logos are trademarks or registered trademarks of SAP SE in Germany and other countries. ITChamps is an independent company and is not affiliated with, endorsed by, or sponsored by SAP SE.

Migration timelines referenced in this article are illustrative only. Actual migration duration varies based on landscape complexity, custom code volume, data quality, organizational readiness, and integration scope. ITChamps does not guarantee specific migration timelines. All engagements are scoped individually following a formal readiness assessment.

No ROI projections, cost savings, or total cost of ownership reductions referenced or implied in this article constitute a guarantee or warranty of specific financial outcomes. Results vary by organization, landscape, and implementation approach.

Statistics cited: Gartner (2024); ASUG/LeanIX (2024); SAP Global Executive Survey (2024). ITChamps makes no warranty as to the ongoing accuracy of third-party statistics cited herein.