update: I managed to upload the mail alert module v3.7.0 (I've found a post that a change must be done in the numbers behind the folder and this worked for me), configuration done - test done - but mails are not coming in - our PS 1.7.8.7 has the Dutch language, can it be that I still need to change anything? the clients are still receiving the confirmation mail from the order.
also in the mail logs, I don't see that the order is send to our mailbox, it's transferred only to the client.