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Decision guide · ERP modernisation

Choosing an ERP: SAP S/4HANA, Microsoft Dynamics, Oracle, Infor, open source

ERP decisions have a ten to fifteen year horizon and tie up a substantial share of the IT budget across it. How large that share turns out, and how often such programmes fail, depends on the organisation and the migration strategy: figures you can rely on belong in your own business case, not in a rule of thumb. Only one date is fixed: SAP has set the end of mainstream maintenance for ECC at 2027, with an option to 2030, which is currently pushing many companies into a S/4HANA or switch decision.

TL;DR

In the mid-market the 2026 ERP decision is rarely 'SAP or not' but 'RISE with SAP vs Microsoft Dynamics 365 vs Infor'.

Who owns this decision

CFO is owner. CIO, COO, sales and production leaders in the steering group. Board as approver.

Key criteria to weight

  • Sector fit and standard processes

    An ERP that covers 80% as standard is 5x cheaper than one with 50% custom code.

  • Cloud model

    RISE with SAP, GROW with SAP, public-cloud editions, hyperscaler hosting differ on sovereignty and TCO.

  • Greenfield vs brownfield migration

    Greenfield = process reset (slower, cleaner). Brownfield = lift-and-shift (faster, technical debt remains).

  • Integration with existing stack

    CRM, HRIS, MES, PLM, BI. Connector library and API maturity.

  • TCO 10 years and implementation risk

    Not just licence but change management, training, sunset of old systems.

  • EU data residency and sovereign options

    Banks, insurers, KRITIS industries often need sovereign hosting.

Step-by-step decision flow

  1. 1

    Mandate and strategy

    Why now? Is S/4 migration mandatory?

  2. 2

    Vendor longlist

    SAP S/4HANA, Microsoft Dynamics 365 F&O, Oracle Fusion ERP Cloud, Infor CloudSuite, Workday Financials, open source for smaller mid-market.

  3. 3

    Detail evaluation

    Sector fit, implementation partners, references, cloud model, sovereignty, exit strategy.

  4. 4

    Implementation partner selection

    Top partners, DACH specialists. Partner selection is its own decision.

  5. 5

    Memo, pilot, board approval

    Decision memo plus 18-36 month implementation plan plus 10-year TCO.

Compliance note

GDPR, NIS2 Art. 21, DORA Art. 28-30 where applicable. GoBD, SAF-T, B2B e-invoicing 2025-2028, retention 6-10 years.

Common pitfalls

  • ERP standard is customised instead of the process. A custom-code graveyard emerges.
  • Implementation partner is selected too quickly.
  • TCO underestimated: sunset of old systems missing from the business case.
  • Sovereignty and exit strategy missing.

FAQ

RISE with SAP or own S/4HANA hosting?

RISE = SAP-managed service on hyperscaler. GROW with SAP is the public-cloud variant for mid-market. Own S/4 installation is exceptional in 2026.

By when must I migrate from SAP ECC?

Mainstream maintenance runs through end of 2027, extended maintenance until 2030. Pragmatic recommendation: decide by 2026, productive by 2028.

How long does an ERP implementation take?

Mid-market 6-12 months. Group subsidiary 12-24 months. Group total 24-48 months.

Run this decision in DecisionOS →What is DecisionOS?