I sent an e-mail to the support e-mail but didn't get a reply yet.

Currently when attaching a file to a PDF, Prince is using "Unspecified" for "AFRelationship".

/AFRelationship /Unspecified

The specification for e-invoices in France and Germany (Factur-X/ZugFerd) requires this to be either "Data" or "Alternative" for the attached XML file, and "Supplement" for any (optional) other attachment.

E-invoices will be mandatory for all companies here from 2026.

I'm using this command to generate the file:

prince invoice.html -o invoice.pdf --pdf-profile="PDF/A-3a" --pdf-xmp=Factur-X_extension_schema.xmp --attach=factur-x.xml

In order to be able generate PDF files compliant with the Factur-X specification, it would be nice if Prince allowed to specify the "AFRelationship" for each attached file separately.

Thank you.

Sorry for the delay in replying, we will add an option for specifying the attachment file relationship type.

No worries, I was just wondering if my email reached you

Thanks, great to hear this!