Decide how far back the target reaches before planning anything else, then run a dependency-ordered wave plan with freeze points, canonical reconciliation keys and rollback boundaries defined by wave rather than by table.
Cutover for a GP migration has one decision that comes before all the others, and it is not a technical one.
Statutory retention. How long records must be retained, per jurisdiction. This sets a floor for the archive, not for the target.
The migration runs as dependency-ordered waves. Each wave depends on the ones before it, and the ordering is about correctness rather than convenience.
A freeze point is one moment at which the source is authoritative for a defined data set. The rules:
The tenth posting rule covers batch posting and opening balance carryforward, and its residue statement is the important part: source year-end retained earnings automation does not map one for one to target cutover steps.
Every one of these is stated at a granularity finer than a single total, and that is deliberate. Aggregate matches conceal offsetting errors with unhelpful reliability: an item-level inventory match can hide a site-level mismatch that nets to zero, and a receivables total can match while the aging profile is wrong.
The cutover posture is stated directly: rollback boundaries are defined by wave and authoritative data set, not by individual table reloads.
One programme-level fact belongs in the cutover conversation. The supported baseline carries a defined end date for enhancements, regulatory updates and technical support, with security updates continuing for a limited period beyond it.
Supported by the source material: the archive boundary as the central decision, the wave ordering, the validation checklist and its granularity, the canonical key set, the rollback posture, and the opening-balance residue.
The archive boundary is the central cutover decision. It sets volume, reconciliation scope, reporting design and cost, and it belongs to the business in discovery. State three boundaries — target, archive, and deliberate disposal — so nothing is left ambiguous.