Does Supplier receive E-mail for acknowledgment if supplier portal is not enabled?

Summary:

We have a scenario where business wants to send acknowledgement required E-mail to the supplier where POs are created with Acknowledgement required. Supplier is not enabled for Supplier portal. The supplier will acknowledge the PO over E-mail and buyer can manually Acknowledge the PO.

But it seems for such POs where supplier portal is not enabled no E-mail notification is sent specifically mentioning regarding acknowledgement is required. We do see supplier communication E-mail but that is different from this.

Is there any option available where acknowledgement E-mail is sent to supplier?

If we need to customize this what would be a good approach?