Lesson 4 of 5
Fallback and continuity
10 min
Every cutover plan should answer a question nobody likes to ask: what if it goes wrong? Fallback planning decides in advance when the team would stop and go back, and what the business does to keep running in the meantime. Having the plan makes it less likely you will need it, because it forces honest decision points.
Decision points in the cutover weekend
- Friday 18:00Business freeze and legacy closeLast legacy transactions; ECC set to restricted access; final extracts
- Saturday 06:00Decision point 1: master dataMaster data loaded and reconciled? If not, stop and stay on ECC
- Saturday 22:00Decision point 2: open items and balancesFinancial data reconciled and accepted? If not, stop or fix within the window
- Sunday 08:00Decision point 3: technical and smoke testsInterfaces, output and smoke tests passed in production?
- Sunday 16:00Final go/no-go and point of no returnAfter this, users transact in S/4HANA and rolling back gets much harder
- Monday 06:00Go-livePlants 1710 and 1720 start shipping from S/4HANA
Each decision point has go criteria and a named decision maker. Before the point of no return, rollback means re-opening the legacy system and discarding the partly loaded production data. After it, real transactions exist in S/4HANA, documents have gone to customers and suppliers, and going back means re-entering everything in the old system. That is why the last decision point comes before the first business transaction.
Rollback triggers
A rollback trigger is a condition, agreed in advance, that makes the team revert to the legacy system. Writing triggers down prevents an improvised decision under fatigue. Examples for Contoso:
- Financial balances or open items not reconciled, with material unexplained differences, by decision point 2.
- Billing output or bank interface not working in production by decision point 3, with no workaround.
- Cutover more than six hours behind plan at decision point 3, leaving no time for smoke tests.
- A critical defect found in production smoke tests that stops shipping or invoicing.
- Is a rollback trigger met?Yes → escalate to the decision maker for rollback · No → continue
- Can the issue be fixed within the remaining window?Yes → fix, re-check, record · No → rollback or controlled go with workaround
- Is a tested manual workaround available for the affected process?Yes → consider conditional go with owner and deadline · No → rollback
Not every problem is a rollback. Most issues found during cutover are fixed within the window, or handled with a conditional go and a workaround. Rollback is for failures that stop the business and cannot be worked around. Make that distinction explicit in the triggers, so the team does not roll back for a minor issue out of caution, or push forward through a serious one out of momentum.
Business continuity
Continuity covers two periods: the blackout, when neither system is available for normal work, and the early days after go-live, when parts of the process may not work yet. For each critical activity, decide how the business keeps running and who owns it.
| Activity | Continuity measure | Owner |
|---|---|---|
| Urgent customer shipments during blackout | Ship the week before; manual delivery notes for emergencies, entered in S/4HANA afterwards | Plant logistics leads, Detroit and Chicago |
| Goods receipts during blackout | Receive physically with paper log; post in S/4HANA on Monday | Warehouse supervisors |
| Supplier payments | Last payment run in ECC before freeze; first S/4HANA run tested in week 1 | Accounts payable lead |
| Customer invoicing if output fails | Invoice PDFs generated centrally and e-mailed by AR team | Maria, O2C key user |
| Credit decisions | Credit team uses frozen ECC exposure report until S/4HANA credit data verified | Credit manager |
Continuity measures for Contoso's cutover. Every step has a named owner.
What would you do?
At Sunday 08:00, Contoso's bank interface fails in production. The fix will take about 10 hours. The first supplier payment run in S/4HANA is planned for Thursday. What is the most reasonable recommendation?
- Plan decision points through the cutover weekend, each with go criteria and a decision maker.
- Agree rollback triggers in advance; the last decision point comes before the first business transaction.
- Plan continuity for the blackout and early days, with a named owner for every step.
- Rehearse workarounds and fallback steps in mock cutovers.
Check your understanding · not graded
Lesson check
1. What is a rollback trigger?
2. Why must the last decision point come before the first business transaction?
3. What does business continuity cover during cutover?
4. Which requirement applies to every fallback step?