The old system keeps running
After the last go-live S/4HANA stayed up as a read-only archive – for looking things up, and with the licence still running. That is the normal state after a replacement, and it is rarely planned for.
Case study: our own replacement
We replaced SAP before we recommended it.
Four companies came off SAP between 2021 and 2023 – and the largest one went third, not first. This page states the dates, the volumes and the part that project reports leave out: switching off afterwards.
The sequence
The main company went third.
22 months lie between the first replacement and the largest. In those months the same migration was done twice at smaller houses – with real business, not with test data. Whoever starts with the biggest company has spent the room to learn before needing it.
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01
March 2021 – PowUnity
The first company off SAP, and a different business model on the same platform: consumer volume rather than industrial B2B. It has since carried 202,073 sales orders. A first move that hurts if it fails, but does not stop the group.
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02
November 2022 – STASTO Hungary
The same migration a second time, now in the industrial process with local language, currency and tax law. 7,710 sales orders since. This is where the migration became a routine instead of a project.
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03
1 January 2023 – STASTO Austria
The main company, on the first day of a financial year. 85,658 sales orders since. By then nothing about the procedure was new – only the size was.
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04
February 2023 – STASTO Serbia
Five weeks after the main company, 3,308 sales orders since. After that seven more companies joined the same platform – none of them from SAP, the most recent in Slovenia in July 2026.
02
Counted, not estimated
What the four replaced companies
carry today.
4companies off SAP
PowUnity, Hungary, Austria, Serbia – between March 2021 and February 2023.
298,751sales orders since
Confirmed orders in those four companies, counted on 17 August 2026.
98 %of the order volume
The replacements are not the small part of the journey. The seven companies that joined later account for the rest.
81,244outgoing invoices in 2025
Up from 12,717 in 2021 – the load the platform carries has grown sixfold.
22months of lead time
Between the first replacement and the main company. That interval is the method, not hesitancy.
21languages, 16 companies
On one platform and one data context, with 118 internal users.
The part that gets left out
Go-live is not the end. Switching off is.
A licence notice turns it into a deadline
SAP sent a breach notice about the compatibility packs; those usage rights expired on 31 May 2026. From that point the archive was no longer a comfortable state but a date.
The data has to come out first
18 tables hold what is relevant for retention: around 60.1 million rows, measured in June 2026. Structured data goes to its own PostgreSQL database, so it stays machine-readable for tax audits.
The invoices are not in the tables
Around 542,000 billing documents exist as PDFs somewhere other than the tables. They must be secured while SAP is still running – afterwards nobody renders them again.
Plan it from the start
Whoever plans a replacement should budget the shutdown with it. It costs more than it looks, it has its own clock, and it is the one step that cannot be postponed once the licence letter has arrived.
What this means for your project
The dates on this page are ours. Yours depend on your enhancement package, your modifications and your retention obligations – and the first of those you can look up today.
The next step