With the release of ArcGIS Pro 3.2, it is necessary for any customers using OSTN15 transformations (geographic transformations WGS_1984_to_OSGB_1936_OSTN15 and ETRS_1989_To_OSGB_1936_OSTN15) to download and install the supplementary ArcGIS Coordinate Systems Data from My Esri. This articles explains what to do if you are affected.