Our scenario:
We are sending a prefilled pdf document to an external user with the instruction to complete the form and return it together with a copy of the id/passport. Which could be one or more pdfs or images.
We've configured a hot-mail-box to check for e-mail having a pdf with a valid barcode. The pdf with the barcode is attached nicely :).
But also want to add the additional attachments.
One should expect that according the documentation the configuration of additional attachment filter would actually add additional attachments. After talking to the support this is only the case when those attachments also have a barcode.
I can see that this behavior can make sense for some cases.
But it should be also possible to add attachments without barcodes. Otherwise we have to upload the whole e-mail, which in preview mode shows attachments like images, but with a low quality.