Match the last old SaaS invoice to the first new one during migration

Use the customer's paid service period and renewal date to establish the billing boundary. One migration date may cover subscriptions with different calendars. For each account, record the last invoice in the old system, its covered period, payment status and the first period to be billed in the destination. Identify any usage billed in arrears that crosses the boundary.

Stripe's toolkit guidance specifically addresses coordinating the new start with the last old charge and canceling the old subscription before it charges again. Treat the sequence as a planned operation with evidence from both systems. An imported subscription and an instruction to cancel later are not a completed reconciliation.

Confirm that the destination can collect by the intended method before moving the account's billing responsibility. Stripe describes payment-data migration and subscription migration as separate processes. A customer record appearing in the new account does not establish that its payment method or subscription configuration is ready.

Use the provider's approved secure transfer process for payment details. Finance can review identifiers, readiness status and exceptions without receiving raw card data. Record customers requiring a new payment method and decide how their service and billing will be handled during the gap, with the commercial owner's approval.

Place the last old invoice and first new preview side by side. Check dates, quantities, prices, credits and any one-time migration adjustment. Two invoices with the same total may still overlap a week; two different totals may be correct if one covers a partial term. Explain the period calculation before accepting the amount.

For illustration, an annual subscription paid through August 31 should not be charged for July and August merely because it moves systems on July 1. The destination needs the approved remaining-service treatment and the correct next renewal. Keep the original payment evidence available so the migration adjustment can be explained to the customer and accountant.

List unpaid old invoices separately from future destination invoices. Decide which system continues collections for each existing obligation and how receipts will be reconciled. Avoid creating a new collectible copy of the same balance without an explicit, reviewed process for the original. Keep old invoice references in any correspondence or mapping record.

Check payment attempts already processing when cutover occurs. A late success in the source system can make a destination collection unnecessary. Maintain a short exception queue for these in-flight items and assign an owner to check their final outcomes before the customer is asked to pay again.

After the first destination bills are issued, reconcile the migrated population to old-system closures and new invoices. Investigate duplicate periods, missing invoices, unexpected prorations and changes in collection method. Keep account-level evidence for corrections so the overall reconciliation does not hide offsetting overcharges and omissions.

Continue the review through the relevant renewal cycles, including annual customers whose first new charge occurs later. A migration can be operationally complete while those later checks remain open. Record their owners and dates in the handover so the ordinary billing team can finish them without reopening the entire migration project.