As mentioned before, the Kepler - Attachment fields | simple & multiple custom field can be configured to store multiple files.
Step 1: Click on Attach files Icon 
and select files.
Step 2: Choose one, or multiple files from the opening window or, drag and drop your Files.
Step 3: At this step, you can:
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3. Add a new version (modified) of an uploaded file, the new version will be attached and the old one will be added to the archive (configuration required: duplicat= false and archive activated)
PS: When users attempting attempt to attach empty files to an issue an Empty File Warning appears, the attachment process is not blocked so users can proceed as needed.
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