21 company codes migrated to SAP S/4HANA, with an ongoing IT-audit engagement.

Starting position

A healthcare group migrates 21 company codes to SAP S/4HANA. The source systems are Diamant and Navision on the finance side and parallel EMR integrations on the operational side. Cut-over runs during live hospital operations, with billing interfaces and an IT-audit engagement that continues into the closing meeting. Data states are heterogeneous, there is no approved maintenance window, and auditable documentation has to exist from day one. The audit risk sits in the source systems and their data states.

Approach

• ◆Built a custom migration script for the source systems: idempotent, repeatable loads with per-record audit logs and a re-run pattern for targeted error analysis.
• ◆Automated the open-items export straight from Diamant (FI: A/R, A/P): basis for closing and go-live.
• ◆Prepared completeness evidence for the year-end audit: every uploaded record traceable in the migration logs, plausibility checked in Fiori.
• ◆Stood up a Power BI cockpit for cut-over status, open-items dashboard and completeness live view.
• ◆Documented every step in a versioned runbook that auditors can read and in-house IT can take over.
• ◆Planned from day one around what auditors request: data extracts, traceability. We know this from our own Big-Four background.

How it works

1. 01
   Discover

   Mapped the source data, defined completeness logic FI/AA/BP/MM, set the audit Definition of Done from our Big-Four background.
2. 02
   Design

   Built the migration script, specified EMR adapters (xViaNova ↔ Navision as the lead integration), set up the Power BI cockpit, versioned and captured in the runbook.
3. 03
   Deliver

   Full test runs against the completeness definition using production data via SAP Migration Cockpit. Cut-over across several weekends, one per company, each on a Saturday or Sunday.
4. 04
   Sustain

   Hypercare phase, ongoing IT-audit engagement with closing meeting, handover-ready for in-house IT with the full runbook.

Outcome

The project ran from Discover through go-live into the still-ongoing hypercare and IT-audit engagement. The migration logs document every uploaded record auditable down to the row (FI/AA/BP/MM). That prepares completeness for the year-end audit. Value correctness is signed off by the client's domain experts, and the role split is documented. The IT-audit engagement under IDW PS 850 / ISA [DE] 315 continues in the closing mandate. The Power BI cockpit and runbook stay with the client and can be run without us.

Why this stack

Custom migration script

Idempotent, repeatable loads for the source systems, extending the SAP Migration Cockpit with re-run and logging patterns for targeted error analysis.

Power BI

Cut-over cockpit and reconciliation live view in one place, shared with the IT audit and steering committee.

Runbook documentation

In-house IT takes over from a versioned runbook that stays auditable and restorable.

IDW PS 850 / ISA [DE] 315

Audit expectations from our Big-Four background apply from day one, not only at closing. The aim is to prevent findings up front.