Dual Maintenance and Retrofit During Transformation

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Dual maintenance and retrofit card

• N = maintenance track for production; N+1 = project track. Changes flow N → N+1 by retrofit only.
• No transport routes from N to N+1; never import ECC transports into project systems.
• Register starts the day the first project system is copied; build it from production import history.
• Every change gets a decision: not applicable (with reason), retrofit, or merge.
• Methods: auto-import (no conflict), semi-automatic (Correction Workbench, BC Sets), manual.
• Across ECC to S/4HANA, review code retrofits even without conflicts; re-enter configuration in CMD.
• Freeze stages: open, soft, hard, cutover; publish dates and an emergency procedure.
• Test each retrofit in CMQ; link evidence to its feature; add critical ones to regression.
• Reconcile before cutover and after the last ECC import; sign the register complete.