Could not find how to do it with qpdf or pdftk or even a gui tool.
Edit:
Solution pdftk A=oldpdf.pdf cat A output newpdf.pdf
This removes all metadata and also the attachments.
Could not find how to do it with qpdf or pdftk or even a gui tool.
Edit:
Solution pdftk A=oldpdf.pdf cat A output newpdf.pdf
This removes all metadata and also the attachments.
Slightly shorter:
pdftk old.pdf cat output new.pdf