An Acknowledgment of Receipt (AOR) is an official letter that IRCC sends you confirming they have received your application and will start processing it. Aor is an official letter that the ircc sends you confirming they have received your application and will start processing it.An Acknowledgment of Receipt (AOR) serves as an official confirmation from IRCC that they have successfully received your application. By signing this document, I acknowledge receipt of the filed document and waive the requirement that I receive notice of this hearing. "AOR" stands for "Acknowledgment of Receipt. Acknowledgement of receipt of the grievance. Generally speaking, employees are asked to sign the document to show they have seen and understood them. Letter of Confirmation of employment from the employer in Canada;.