Thanks for your reply. I think however, I did not make myself clear in my question. The reason that the new file would have a different extension is that it would be a file of a different type. Let me try to make myself clearer.
I have a managed document, "Price LIst.doc". The document is currently a word document, a .doc file.
Someone is tasked with updating the price list. They feel that it should be a PDF - maybe they decide that it is easier to send PDFs to the print shop, so we should work in that format. So, a new price list is created.
At this point I think the document "Price List.doc" should be updated with "Upload new version", selecting and uploading the new version, "price List.pdf". The name would change, and the version would be updated.
I mean, why not? What do I care, the document is the document, isn't it? The file format, the details of which software created is technical. There is only one document, which has been through two versions.
Thumbnail and mime-type should not fall over, the .doc is a word document, the .pdf is a PDF. Simple.
Or is it? Is there no way to work like this? Do I have to delete the old .doc and upload a new PDF, thus losing the version history?
Andrew