To upload older bank transactions (e.g., from last year) into QuickBooks Online (QBO), you can manually import them using a CSV file or connect your bank account if your bank supports longer historical downloads. Manually Upload Past Bank Transactions (CSV Upload). If you already connected your bank and didn’t choose the correct date range, disconnect the bank and reconnect it with the full range (if your bank allows). Avoid duplicate entries by checking for overlap when importing CSV files. You can always exclude duplicates during the review stage in QBO.