Most vendors bring your accounts across as opening balances at a cut-off date, with unpaid invoices carried over one by one or as a single figure per matter. Payment status goes wrong around the cut-off, when clients pay invoices the new system doesn't know yet. Pick a month end, bill and reconcile before you switch, keep the original invoice numbers, and keep collection and chasing running outside the migration.
In this article
The short version
- Some systems carry each unpaid invoice across individually while others bring one balance per matter, which leaves later payments to be allocated by hand.
- Payment status breaks around the cut-off through payments in transit, renumbered invoices, unapplied credits and payment requests already sent.
- Rule 8.3 still requires every client account to be reconciled at least every five weeks, so pick a cut-off month end that fits that cycle.
- Before switching, bill work in progress, allocate unapplied receipts and credits, reconcile the old system and check the new opening balances against it.
- Adfin sits alongside the practice management system, so clients can keep paying the invoices and payment links they already hold during the switch.
Where payment status breaks during a switch
The new system goes live on Monday. On Tuesday a client pays £2,400 against an invoice number the new system has never heard of, a fee earner asks whether last week's bill was paid, and nobody's sure whether the reminders stopped when the old system was frozen.
Most of the trouble comes from four places:
- Payments in transit. A payment made the day before cut-off can arrive after the old system is frozen.
- Changed invoice numbers. If invoices are renumbered on import, a client paying the original reference won't match anything.
- Unapplied credits. A credit or part payment that wasn't allocated before export can leave an invoice looking unpaid in the new system.
- Payment requests already sent. Links and reminders sent before the switch still point at the old invoice.
What your new system will bring across
Read your new vendor's migration pages before you sign. The common pattern is an opening balance at the cut-off date for each client and office ledger, with older financial history kept as read-only records or uploaded ledger cards.
For payment status, the biggest difference is how unpaid invoices come across. Some systems, such as LEAP, bring each unpaid invoice over individually, while Clio brings accounts receivable across as one balance per matter. If open invoices arrive as one figure per matter, your new system will know what's owed but not which invoice a later payment belongs to, and you'll be allocating by hand.
Ask the vendor, in writing: will open invoices keep their original numbers and remaining balances, will client money balances migrate and in what form, what has to be recorded manually after the cut-off, and how long you'll keep access to the old data.
A cut-over plan for the accounts side
The SRA Accounts Rules don't change because your software does. You still need client ledgers, a cash book and a central record of bills, and rule 8.3 still requires a reconciliation of every client account at least every five weeks, signed off by the COFA or a manager.
Time the switch around that. Say your last signed reconciliation was at 31 August. If you cut over at 30 September, you can reconcile the old system at that date, check the new system's opening balances agree to it, and have the first reconciliation in the new system signed off by 5 October.
- Pick a month end that fits within five weeks of your last reconciliation.
- Bill outstanding work in progress, so fewer unbilled items are left behind.
- Allocate unapplied receipts and credits to the bills they belong to.
- Reconcile the old system at the cut-off date and get it signed off.
- Export client ledgers, the cash book and the bills register to somewhere your accountant can reach.
- Freeze the old system and post anything received after cut-off in the new one.
- Check the new opening balances and open invoices against the old reconciliation.
- Keep read-only access to the old system for as long as the outgoing vendor allows.
How to keep money coming in while you switch
A system change can pause billing for a few days without pausing collection. If your invoices and payment requests run through a payment platform that sits alongside the practice management system, clients can keep paying the invoices they already have while you set up the new one.
Adfin works that way. It takes invoices as uploaded PDFs, CSVs, Excel files or images, so invoices exported from the old or the new system can go straight in, and the payment links clients already hold don't depend on the practice management system. Adfin matches each payment to its invoice, including part payments, overpayments and payments with a missing reference, which gives you a clean list to post. Once the new system is live, someone on the team needs to own getting new invoices across and checking the two agree.
Chasing is usually the first thing to slip while the accounts team is busy with a migration. Adfin's Customer Agents keep following up unpaid invoices over email, SMS or WhatsApp on the schedule you've set, with your team approving what goes out, so the switch doesn't leave a gap in reminders.
Before the cut-off, also confirm with your payment provider that payout accounts, references and any direct debit mandates are unaffected, and that every mandate is still linked to the right client and matter afterwards.
Common questions
Do unpaid invoices migrate to a new practice management system? It depends on the vendor. Some bring each unpaid invoice across individually and others bring one balance per matter, so ask before you agree the cut-off.
Do client account balances come across when you change system? Usually as opening balances at the cut-off date. Check the exact form with your vendor, since vendors' own help pages don't always agree.
When should a law firm cut over? A month end is the usual choice. Pick one that lets you reconcile in the old system and complete the first reconciliation in the new one within five weeks of the last.
What happens to a payment on an old invoice after the switch? It's posted in the new system against the imported invoice, which is easy if invoices kept their original numbers and harder if they came across as one balance per matter.
Does changing system affect the five-weekly reconciliation? No. The requirement is the same whatever system holds the records, and a reconciliation at the cut-off gives the new system a checked starting point.
Do direct debit mandates need setting up again? Mandates sit with the payment provider that collects them, so changing practice management system doesn't cancel them by itself. Check each one is still linked to the right client and matter.
Sources
- Clio - Clio Manage Data Migration Overview (accurate as of September 2026) https://help.clio.com/hc/en-us/articles/9813884849947-Clio-Manage-Data-Migration-Overview
- Clio - Prepare Data For Migration (accurate as of September 2026) https://help.clio.com/hc/en-us/articles/50633872928539-Prepare-Data-For-Migration
- LEAP - Transitions - How Will My Imported Data Be Displayed? (accurate as of September 2026) https://community.leap.co.uk/s/article/How-will-my-imported-data-be-displayed
- SRA - SRA Accounts Rules (accurate as of September 2026) https://www.sra.org.uk/solicitors/standards-regulations/accounts-rules/
- Adfin - Credit control (accurate as of September 2026) https://www.adfin.com/credit-control
