An application number is assigned to an application for permanent residence when Immigration, Refugees and Citizenship Canada (IRCC) begins to process the application. It is distinct and different from the unique client identifier (UCI), IRCC’s client ID. A person will have the same client ID, but may have multiple application numbers – one for each application. Moreover, multiple client IDs can share the same application number, if they apply together for permanent residence on a single application. When combined with the family status identifier, a common application number can be used to link immigrant family members together.The application number is represented by the APPLICATION_NO variable in non-legacy landing data, and by the APPLICATION_CODE_NO variable in legacy landing data. The application number is not included in temporary resident data in the repository.