CASRA has announced that, since January 2020, their X-ray Tutor 4 (XRT4) is in operation at all 89 airports in Canada under the supervision of the Canadian Air Transport Security Authority (CATSA). The project for the transition from XRT3 to XRT4 started in spring 2019. XRT4 will be used by CATSA for initial and recurrent computer-based image interpretation training and testing for another three years, with the option of a five-year extension.