No. The client keeps their bookkeeping system and their bookkeeper keeps working in it. AllDone starts where the bookkeeping stops: you export the trial balance, the general ledger, the profit and loss and the balance sheet, and AllDone does the year-end file, the accounts and the corporation tax computation from there.

Their bookkeeping software records the transactions: invoices, bills, bank, VAT returns, payroll postings. It carries on doing that unchanged.

AllDone takes those records as they stand, checks and reconciles them, maps them to the statements, finds the year-end adjustments, computes the tax and produces the file. Nothing is posted into the client's ledger by AllDone.

Your filing software takes the final trial balance and the tax figures and files.

AllDone never writes to the client's ledger. What it produces is a set of importable files: the year-end journals in the layout each bookkeeping system expects, and credit notes, invoices and bills where an adjustment has to touch a customer or supplier balance rather than a nominal. You decide whether to import them or to correct the source transactions instead.

Because it works from exports rather than a connection, it does not matter which system the client uses, and a client who moves from one system to another changes nothing about how the job runs.