I upgraded to Sigil 0.6.1 today, installing it right over 0.60, but when I imported a book that was converted by Calibre I kept getting an error message about malformed (or poorly formed) xml pages. It was a window that popped up and listed I think every single file in the book. So I reinstalled 0.6.0 and no error messages when I import the same book. For now I will keep 0.6.0 installed.
Is this a bug?