Hello, we write ebooks in German and in the case of one ebook, the name of the file included an umlaut "Ã¼".
FYI in this case the pdf stamping does not work. I di not get an error. Just when I did test purchases, I saw that the pdf stamp was not working.
I changed the "Ã¼" with "ue" and the pdf stamp worked fine.
Just FYI for other users.