Data migration when changing software: what to arrange up front
What migrates and what does not when changing packages, the best moment to switch and the checkpoints for the migration plan. Including retention.
The short answer
When changing software, the chart of accounts, contacts, open items and journal history usually migrate well, mostly via an audit file (XAF). Document attachments, processing rules and settings migrate poorly or not at all. Knowing that in advance lets you build the plan around it: move the hard figures across verifiably, and for the rest choose deliberately between rebuilding and archiving in the old package. The switch itself is planned on a year boundary, or failing that a quarter boundary, never in the middle of a filing period.
The migration is usually not the hardest part of a switch; that is choosing the new package. But a sloppy migration can still ruin a good choice, because the trust of team and clients in the new environment is decided in the first weeks.
What usually does migrate
- The chart of accounts. Account numbers and descriptions come across via the audit file or an import. Watch the mapping to VAT codes: that is package-specific and almost always has to be rebuilt.
- Contacts. Customers and suppliers with name, address and VAT number. Pollution migrates along happily, so this is the moment to clean up duplicate and dormant contacts.
- Open items. The outstanding receivables and payables as at the switch date. This is the list clients notice first: a payment reminder for an invoice already paid is the worst possible start in a new environment.
- Journal entries and history. Via XAF the posting history comes across per year, usable for comparative figures and the year-end. Do not count on every detail arriving; see the next section.
- Opening balance. Effectively the closing piece: the closing balance of the old package becomes the opening balance of the new one.
What migrates poorly or not at all
- Document attachments. The scanned invoices and receipts behind the entries are not in an audit file. Some vendors offer a bulk export with a mapping file, others only individual downloads. This is the biggest surprise in most switches, so ask about it before you cancel. It belongs to the data portability you ideally arrange at purchase, see Licence holding.
- Processing rules and settings. Recognition rules, recurring entries, automatic codings, templates: everything that made the old package smart is package-specific and has to be rebuilt or relearned.
- History at line level. XAF contains a lot, but not everything: payment allocations, matching history, time records and package-specific fields are usually lost or arrive flattened.
- Users and permissions. Authorisations are set up fresh in the new package, which is also an opportunity to review them critically instead of copying years of accumulated rights.
The strategic choice is therefore: how much history do you actively move? Many firms choose to migrate two to three years of journal history for comparative figures, and to cover the rest through read-only access or an archive of the old package.
The best moment to switch
The year boundary is the natural moment. The annual report closes the old package, the opening balance opens the new one, and comparative figures are neatly separated per year. The downside is that everyone picks that moment: vendor and firm are at their busiest in December and January, and it coincides with the year-end work.
A quarter boundary is the workable alternative, ideally aligned with a VAT period: the old package files the return up to and including the old quarter, the new one starts clean. Switching in the middle of a period produces a return that has to be assembled from two systems, and that is asking for reconciliation differences.
For a firm moving dozens of administrations there is one more rule: not everything at once. Migrate in waves, starting with a pilot group of five to ten administrations whose owners can tolerate something going wrong. The lessons from the pilot turn the following waves into routine.
The plan in phases
Phase 1: preparation (4 to 8 weeks before the switch)
- Inventory the export options of the old package: XAF per year, contacts, open items, document attachments.
- Clean up: deduplicate contacts, resolve or write off old open items, empty the suspense accounts.
- Set up the chart of accounts and VAT codes in the new package, firm-wide and not per administration separately.
- Trial-migrate one representative administration, including all the checkpoints below.
Phase 2: the switch itself
- Close the old period completely: all bank transactions processed, return filed, period locked.
- Run the exports and imports: chart, contacts, open items, history, opening balance.
- Secure the document attachments, in the new package or in an organised archive.
Phase 3: checks before go-live
Three reconciliations are mandatory, per administration, recorded with date and name:
| Checkpoint | What you compare |
|---|---|
| Trial balance | Trial balance of the old package as at the switch date against the opening balance in the new one, to the cent |
| Open items | Receivables and payables list old against new, per item and in total |
| VAT positions | VAT liability and amounts still to be declared, old against new, reconciling with the last return filed |
If one of the three does not reconcile, you do not go live. A difference you let pass now returns in every monthly close and in the year-end, see the reconciliations in Setting up the monthly close.
Phase 4: aftercare
- Run the first monthly close in the new package with extra attention.
- Rebuild processing rules and automation; expect the first weeks to involve more manual work.
- Only cancel the old package once the first return and the first close in the new package have gone well.
Retention and the old package
The statutory retention obligation of seven years (and ten years for immovable property) does not disappear with the old subscription. The old administration must remain accessible, including the digital files in their original form. There are three ways: read-only access with the old vendor for the retention period, a complete export including attachments in an organised archive of your own, or moving the full history into the new package. Record which one you choose and verify that it actually works: an export nobody can open does not count. See Record retention obligations for the full requirements.
Taking clients along in the switch
For the client the switch is not a project but a surprise, unless you announce it. Three things usually suffice:
- One message in advance covering what changes on their side: new login, new app for receipts, new email address for invoices. No more than that; the rest does not interest them.
- Arrange the bank feed first, because it often requires an action from the client themselves and without the bank everything stalls.
- Actively check in during the first weeks on whether sending in receipts and invoices is working. A client who hits a wall twice falls back on the shoebox, and that behaviour takes months to undo.
Also announce what the client gains: faster processing, more current figures, fewer questions after the fact. A switch presented purely as an internal firm operation feels to the client like hassle without a reason. If you want to see how a switch to Giroo works and what is involved per administration, book a demo and bring one of your own audit files.
Content reviewed: August 2026.