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. If we start processing your application, we'll send you an acknowledgement of receipt letter or email with an application number. AOR means "Acknowledgement of Receipt" meaning a letter that they send stating they have received the application. This publication has been prepared to provide a compilation of standard requirements, called.