HiYou can do this in the Last Updated Module but not in the main displays. Think it could be useful to have this as another facility.
Presently working on the 3.9.8 update which will be after the bugfix 188.8.131.52 update.
I am sure you would still want users to see those Downloads that have not been modified, especially the new ones!
In the present listings of Downloads it can show a modified flag but for this to appear you have to mark the update as having been modified. Can avoid that and just list those Downloads with a Modified date. But beware if showing say a subcategory where no modifications have been made to any of its downloads then nothing will be shown. Not sure if you would want that.
Perhaps an alternative is to have a new Menu item like the List all Downloads but as List all modified Downloads.
Could you let us know which might be the preferable way as you see it.