Hi,
There is no translation for it as that's the default OK button of the Vex popup library.
Try adding the code:
else{
$extra_data[] = '
window.cartNotifyParams.cart_params = {buttons:[
{text:"'.JText::_('HIKA_OK', true).'",type:"submit",className:"vex-dialog-button-primary",click:function continueClick(){}}
]};';
}
after the code:
if($link_to_checkout) {
$extra_data[] = '
window.cartNotifyParams.cart_params = {buttons:[
{text:"'.JText::_('PROCEED_TO_CHECKOUT', true).'",type:"button",className:"vex-dialog-button-primary",click:function proceedClick(){window.location="'.$url_checkout.'";}},
{text:"'.JText::_('CONTINUE_SHOPPING', true).'",type:"submit",className:"vex-dialog-button-primary",click:function continueClick(){}}
]};';
}
in the file plugins/hikashop/cartnotify/cartnotify.php and that should use the HIKA_OK translation instead of the default Vex OK button.