Since version 2.9.4 the plugin removed the ability to update the PDF invoice when it already has been sent to the customer. If in what manner you still want to update the invoice, you can do so by resetting a custom field.
- Go to the ‘Edit Order’ page.
- Change custom field ‘bewpi_pdf_invoice_sent’ value within custom field widget to 0.
- Refresh the page and an update button will appear.