Beginning of June, the historical list of object types in SIMBAD will be replaced by a reorganized list, based on physical properties, and on the evolutionary stage for stars. It will enable a more interactive search, and will provide minimal definitions. The hierarchies between object types will evolve: for instance, a RR Lyrae Star will still be in the hierarchy of Variable Stars, and also in the hierarchy of Horizontal Branch Stars.

If you are using the hierarchies in scripts, you might have to adapt your scripts to the new description.

Please, have a look to the documentation on object types in SIMBAD.