Once a batch of publisher files has been uploaded and linked in Drupal, you'll need to ensure that the correct publication date is associated with each of the files.
When dealing with publisher files, you'll need to copy the publication date that is in the main record or "node" to the publication date associated with the specific file or "field collection" (i.e. the file resource).
You can update the publication dates for files in bulk.
File Attachments: Date Created Values - Null Dates(under Promoted Items)
Date (node)field. This is the publication date of the book, which you'll need to copy over to the
Date Created (File)field.
issued, or nothing at all. Each of these date types will need to be copied over separately. Let's start by copying over the issued dates, which is the most common date type.
Copy Dublin Core Date from Node to Field Collection
issuedas the date qualifier to copy over
Date Created (File)field now contains the issued date
Date (node)and copy over the
copyrighteddate qualifier to the files. For those files that don't state the date type, select the
No Dublin Core Qualifieroption when copying the date to the files.