Sage to Odoo migration: a controlled UK delivery plan

Create a migration register before extraction. Each row represents one logical object and has a named business owner, source location, target purpose, selection rule, quality assessment and acceptance method.

• Accounting foundation: companies, currencies, financial years and periods, chart of accounts, taxes, journals, analytic dimensions and payment terms. Decide which are configured deliberately and which are imported.
• Parties and operational masters: customers, suppliers, contacts, addresses, products, services, units of measure, warehouses, price lists, projects and employee-linked records where required.
• Open finance documents: unpaid customer invoices, supplier bills, credit notes, payments in transit and other items needed to reproduce receivables, payables and bank positions at cutover.
• Opening positions: trial balance, receivables and payables control, stock quantity and valuation, bank balances, foreign-currency balances and any project or analytic balances needed for future reporting.
• History and evidence: closed transactions, line detail, attachments and audit material. Choose the operational history to load, the archive to retain and the access and retention controls for each.

Do not migrate a record simply because it can be exported. Conversely, do not discard history merely to shorten the import until finance, operations and any relevant adviser have agreed the reporting and retention consequences.

Choose a cutover date and obtain the source reports that will serve as the reconciliation baseline. The trial balance, aged receivables, aged payables, bank balances and stock valuation should use the same moment and accounting basis. Finance agrees how unposted source documents, partial payments, credit notes, foreign currency and rounding are handled.

Load opening balances only after their accounts, partners, products, currencies and dimensions have been accepted. Compare target results back to the source at the agreed detail level. A suspense or migration-clearing account may be useful in a designed balancing entry, but it is not a place to leave unexplained differences.

VAT treatment needs explicit accountant review. Check that tax codes, tax accounts, reporting periods and open-document tax values support the intended VAT100 workflow. Odoo 19 provides a VAT100-ready tax structure through its UK localisation; that does not make every migrated code or opening entry correct for the organisation.

The Odoo 19 UK localisation documentation is the current product reference. Use the MTD readiness checklist to connect migration evidence to digital records, digital links, HMRC authorisation and submission review.

A mock go-live uses the planned sequence, representative final data and the people who will perform the real tasks. Time each dependency without turning the rehearsal into a promise of elapsed project duration. Record where extraction, cleansing, review or external access creates waiting time.

The cutover runbook names the freeze rules, final extraction time, delta handling, import operator, reconciliation owner, integration switch, smoke tests and decision authority. It also defines what happens if a critical reconciliation fails: correct and rerun, extend the freeze, use a documented fallback or stop the release.

Hypercare starts with named triage routes and local champions. Review operational evidence such as invoice processing, receipt matching, bank reconciliation and stock movement completion. Close migration only when the agreed records and processes are accepted, not when the last file has been uploaded.