Here is how to update files:
- Click on the file number
- Follow the link to "upload a new version of this file"
- Upload the new file - you can name the new one any way you like (keep it the same or change to something new - it makes no difference)
- When you see the little [B] next to the file description, you will know your replacement was successful
It might appear to be the old version if you view it for a couple of days when logged out, because the site's cache hasn't been updated, but the new one is what will actually download.