When a newer version of an existing file needs to be updated on a website use the "replace file" option rather than just uploading the new file and leaving the old file.

Steps to replacing a media file

• Locate the existing file on the Media content page of the website.
  • Use the search filter to locate the existing file if necessary.

• Once you have found the file, click the Edit button.
• Under the Replace file section, select the Choose File button to select the updated file from your computer.
  • We usually recommend leaving the "Overwrite original file" selector unchecked. If unchecked, the filename of the replacement file will be used and a new direct URL to the file will be created. 
  • When the box is checked, contents of the new file will be written to the old file, and it will retain the same filename and direct URL. Checking the box is only recommended for document files (e.g. pdf, docx, etc.) accessed directly and not through a media entity placed within the website. Examples would be browser bookmarks, hard-coded links in emails, documents or external websites.