
I use Google Drive to share a number of documents at work, including PDF documents. I'll share a Google Drive link with everyone, but when I update the file, I don't want that link to change.
Updating the PDF without altering the Google Drive URL isn't nearly as intuitive as it should be, so here's a little tutorial as to how I do it.
In Google Drive, select the document you want to update, click the "more" menu and choose "Manage revisions...".
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In the "Manage revisions" dialogue box, choose "Upload new revision" and upload the updated file.
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If you'd like to get rid of previous revisions, as I do, simply click the x next to the older version and then "Delete now".
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That's it.