To open an RSTAB file in RFEM, you must change the file type to either "File type RSTAB" or "All files" in the "Open" dialog. This will display not only the RFEM files but also all RSTAB files stored in the selected directory. After opening the RSTAB file, the model can be saved as an RFEM file and further edited.
It is important to note, however, that already created printout reports or input data in add-on modules, for example, will not be transferred.