My information is based on the assumption that the outside source also has a Egnyte account and access to the folder where they keep uploading the updated copies of documents. Now Egnyte does offer file versioning. Meaning, Egnyte automatically creates a new version of a file whenever you/other user saves and closes an existing document.
If a file has mulitple versions, then the number indicated next to the icon that looks like a clock is the file's version count. Clicking the version icon reveals past editions of the document. You can also promote an earlier version of a file so that it becomes the current version. You can supersede your version of the file if it is buried under the other versions or simply upload your version of the file as the last version. This will still make your version as the most updated & current version.
Let me know if the situation is different from how we assumed. If it is, then a little more information on what you wish to acheive will be a great help.
PS. Help others find answers by selecting "Accept as Solution" if a post answers your question."