Not the OP, but 98% of the time that someone sends me a .key file for a Mac Keynote presentation, my Keynote application is out of date and cannot open the file

Not the OP, but 98% of the time that someone sends me a .key file for a Mac Keynote presentation, my Keynote application is out of date and cannot open the file. Additionally, it sometimes cannot update either, unless other components are updated, such as the entire OS itself. A bare minimum requirement for me would be, "a computer can be reasonably expected to open the file". Yes, a computer without the correct application installed could not reasonably be expected to open the file. But here is a computer, perfectly capable of displaying the file, but choosing not to do so. Note that these are not files that are created with the new Keynote that I may not have installed. These are normal Keynote files created in the same version I have - but now my version isn't good enough to open files any more, it would seem. A piece of paper would never do that.