Many PDF readers for smart phones (Android/iphone) and tablets manage the pdf files based solely on the Title and Author fields in the PDF file. While for this is fine for your average book, it is not all that helpful with manuals that tend to have abbreviated or no data in the title/author fields.
How to fix? Easy. Go get Calibre. Drop the PDF files on to the running Calibre. Edit them by hitting the E key.
In my case, I edited the “Title”, “Author”, “Tags”, “Publisher” and “Languages”:
Calibre doesn’t modify the PDF files themselves so I will need to export the files to a custom directory. In Calibre nomenclature, this is “Saving”. Highlight all the titles you want to export and hit “S” twice. Why twice? No idea. Choose the directory.
You can now copy the exported PDF files to your phone, tablet, whatever without fear of the v2.006 version of the PDL Book being rejected by Aldiko because the v2.004 version is already added.