ERP migration: how much history to move and what to archive

Why a fixed number of years is the wrong starting rule#

A fixed number of years is the wrong starting rule because each record type has a different job after go-live. Open sales orders must work on day one, last year's shipments feed the demand forecast, and a closed NCR from long ago only needs to be found when a customer asks. One cutoff date applied to all of them either overloads the conversion or strands records people still use.

The better question is who reads each record after cutover, and how. Records the new system must act on, calculate from or report against belong in it. Records people only look up belong in an archive they can search without calling IT.

A rule of thumb by record type#

A practical rule of thumb sorts each record type into what moves into the new ERP and what goes to the archive, then adds the obligation that sets how long the archived copy must survive. The split below is a common starting point for a mid-size manufacturer; your auditors, customers and planners may move a row.

What planning, costing and reporting actually need#

Planning, costing and financial reporting are the usual reasons to carry closed history into a new ERP, and each needs less than teams assume. MRP and demand planning read shipment or usage history to set forecasts, safety stock and reorder points, but they normally work from history summarized by item and period, not from every order line.

Cost accounting wants current standards and enough recent actuals to explain variances. Financial reporting wants prior period balances so comparative statements and budgets run in the new system. Ask each function lead which reports they will open in the first months after go-live, and trace each report back to the history it reads.

• 1Which reports and screens will you need in the first months after cutover?
• 2Which of them compare against prior periods, and at what level of detail?
• 3Can a summary by item, customer or period replace transaction detail?
• 4Who looks up closed transactions today, how often, and for what reason?
• 5Which records must link to attachments, such as signed quality dispositions or certificates?

The retention overlay: how long history must stay readable#

The retention overlay is the set of obligations that decide how long each record type must be kept and retrievable, whatever the migration does with it. Tax and audit requirements, customer quality agreements, lot traceability commitments, warranty periods and product liability exposure each set a floor, and those floors differ by record type.

Treat the overlay as a separate decision owned by finance and legal, not as a side effect of the conversion scope. If your written retention schedule predates the ERP being replaced, update it before cutover, and record which archive holds each record type and who can retrieve from it. Retention periods come from statutes, contracts and counsel, so confirm them for your company rather than borrowing another firm's schedule.

Tax rules show why one cutoff fails. The IRS says records supporting income, deductions or credits are generally kept until the period of limitations for that return runs out, generally 3 years and longer in some cases. Employment tax records are kept at least 4 years after the tax becomes due or is paid, whichever is later. Records relating to property, such as equipment purchases and depreciation, are kept until the limitations period expires for the year you dispose of the property, so fixed asset history on a long-lived press or machining center may need to stay readable for decades. This is general information, not tax advice; confirm periods with your tax adviser.

What each extra year of converted history costs#

Each extra year of converted history adds mapping, cleansing and reconciliation work, and that work lands on the same finance and IT people running the cutover. Old records carry retired item numbers, merged customers, changed units of measure and earlier versions of the chart of accounts, and each one needs a mapping rule and a test.

Reconciliation is the hidden cost. Converted history has to tie back to the legacy system, and someone in finance has to sign that it does. Period balances reconcile quickly; years of line-level detail rarely do. Ask the implementation partner to price history conversion as a separate line so the trade-off is visible to the CFO.

How should you choose an archive format?#

An ERP archive format should be chosen by who will search it, for what, and for how long. A format only IT can query fails the controller answering an auditor and the quality manager answering a customer.

Illustrative: a kitchen equipment maker sets its cutoff#

Illustrative: a fictional maker of commercial fryers, griddles and ovens is replacing an on-premises ERP it has run for many years. The implementation partner proposed converting all history. The CFO instead asked each function what it would read after go-live.

Planning needed shipment history by item and month for forecasting. Finance needed opening balances and prior-year period balances. Service needed serial numbers, build dates and bills of materials for every unit still in the field. Quality needed nothing converted, only searchable access to closed NCRs and RMAs with their photos.

The company migrated open items, summarized demand, period balances and serial-level build records, and kept the old database as a read-only reporting copy with a data dictionary. The conversion scope shrank, and the archive later became the basis for reviewing whether service and quality history could be licensed.

Where licensing fits, and how SourceX approaches it#

An ERP migration is a natural moment to review whether archived history could be licensed, because the records are already being extracted, documented and moved somewhere the company controls. Closed orders, quality records and service history with linked outcomes can interest AI developers, and the work that keeps an archive readable is the same work a licensing review needs.

The first SourceX step is a metadata-only fit check on the archive: systems, years covered, record families and known restrictions such as customer-owned drawings. If the company proceeds, the SourceX five-step transaction covers Supply, Rights, Preparation, Approval and Delivery, with personal and confidential details removed and nothing released without the company's approval. The archive is licensed, never sold outright, and ownership stays with the company.