Thanks for the clarification.
I have succeeded in installing the extensions using yesterday’s preview release version. But I still have two other questions.
I want to export deformable transform, but when I install “SlicerRT” extension, “DICOM Registration Export” module didn’t show up. I have followed this thread but don’t know how to use that? Could you give some advice?
I was a bit confused about the warning(?) in Python Interactor (shown below). I have installed “SlicerRT” extension and also succeeded in importing RT structure, but the warning(?) still existed? Does it make any difference?