Compatible EXCEL format

Turns out all I really had to do was add one more piece of XML metadata which wasn’t in any of the examples I’d previously found

Now

  • Microsoft Office 2011 for Mac, still works fine
  • Excel version 15 for Mac will now open it just find (per Simon Berridge)
  • Excel 2007 and Excel 2010 for Windows, open it, but just with a warning that the file extension doesn’t match

these are mentioned on https://en.wikipedia.org/wiki/Microsoft_Office_XML_formats

Which is where (3 weeks ago) I found that missing piece :slight_smile: