Make uploads mandatory for submission and prevent authors from uploading their files later

When authors submit their contribution, we would like to make their file upload mandatory.
We do not want that they upload their files at a later time.

How can we handle this requirement?

A remark in advance:
In general, we recommend allowing authors to update their submission until the deadline to make sure that all authors receive the same conditions for their submission. Furthermore, it’s a very common and therefore expected feature that authors can correct their submission and update their upload until they feel they are ready or the deadline has passed. Therefore, if you want to start with the reviewing process before the deadline has passed, we recommend using the “Finalize” function for authors as described here:
Allow authors to finalize submissions before end of the submission period

Of course, you cannot force authors to upload a file, but you can prevent them from skipping the upload process by making the following changes.

When authors submit a contribution that requires an upload, by default the section “Upload File(s) Later” with the button “Save Submission, Upload File(s) Later” will appear (see image 1). The idea behind this workflow is that authors should be able to upload files until the deadline, even when during the initial submission their files are not ready.

However, you can delete the wording of this section and the button for later uploads to make them both disappear.
Please proceed to the page “Wording and Phrases”:
Overview => Settings => Wording and Phrases
Enter the language key “S_NEWPAPER_SKIPUPLOAD” to edit the title of the section and the language key “S_NEWPAPER_SUBMIT_SKIPUPLOAD” to edit the description of the upload button. Click on “Edit Phrase” in each case (see image 2). On the next page, delete everything in the text field and save your settings.
Now, the section title and the button for later uploads are no longer visible (see image 3).

Please remember to test your settings.