What is the ruling on shaking hands with the wife of the maternal uncle of one's mother?

The wife of the maternal uncle's maternal uncle is a non-mahram, just like the wife of the direct maternal uncle and the wife of the paternal uncle. It is not permissible to shake hands with her, nor with her daughters, nor with the daughters of the maternal uncle's maternal uncle, because they are not mahrams. Previous fatwas have clarified the impermissibility of shaking hands with a non-mahram woman, although some jurists differ regarding shaking hands with an old woman.