In order to change the invoice date, simply add the following filter to your themes functions.php
/**
* Change invoice date to order date in order to regenerate old invoices and keep the date.
*
* @param string $invoice_date date of invoice.
* @param BEWPI_Abstract_Invoice $invoice invoice object.
*
* @return string needs to be in mysql format.
*/
function change_invoice_date_to_order_date( $invoice_date, $invoice ) {
// get_date_paid() or get_date_created().
$date_completed = $invoice->order->get_date_completed();
if ( null !== $date_completed ) {
return $date_completed->date( 'Y-m-d H:i:s' );
}
return $invoice_date;
}
add_filter( 'wpi_invoice_date', 'change_invoice_date_to_order_date', 10, 2 );