How to override date formate for invoices generate by invoice plugin?

Hello,
I want to override date format from 2019-04-29 to 29-04-2019 ( www.screencast.com/t/cG2fpq6aaIL )
in all invoices generated

I have already overridden all the other texts for the english language file so that when I update the component the overrides are still there

but I don't understand how to do this for the date format

I am using the hikashop_attachinvoice plugin to generate the invoices, not sure if this is related...

all I see in the invoice.php file is (I have overriden the original file already to apply other changes)

<?php
					if(!empty($this->element->order_invoice_created)) {
						echo JText::_('DATE').': '.hikashop_getDate($this->element->order_invoice_created,'%d %B %Y');
					}else{
						echo JText::_('DATE').': '.hikashop_getDate($this->element->order_created,'%d %B %Y');
					}
				?>