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.The completed form will be kept in the record for two years. The PDF file says (This is to acknowledge receipt of your application for Canadian Citizenship. If we start processing your application, we'll send you an acknowledgement of receipt letter or email with an application number. Terms of Use For Our Customers in the United States and Canada. For example, a pilot should expect to find air traffic at any time or place.