Is Microsoft inside my iMac? [View all]

I have been using Microsoft Excel spreadsheet (and Word) since forever. More than 30 years. First it was Microsoft Works and then Office. I had an Office for Students when I got my Mac in 2011 and then another program two years ago with my then new iMac.

I have been getting one of those messages that it was time to update or upgrade at cost, of course, and just ignored.

But in the past couple of days. all my spreadsheets have a warning on top of them to upgrade and update. How did they get into them? They are only on my desk iMac, no cloud or anything like that.

I don't mind updating but I want to make sure that I will still be able to open old workbooks. And.. they do have some glitches that I once tried to ask on their Facebook and never got a reply (but a few "likes&quot

Anyone? I am asking here because they are for the Mac..