IIRC not for Word file formats. Usually only the previous version would definitely convert, any older and things started breaking. And it would always save in the newest version by default so everyone else has to update to edit your file (there were free readers, but they were separate programs and I don't know how popular they were).
Yeah I remember as a kid saving a file with Word 97, then opening it on a different computer with Word 95, and there was a box between every pair of characters. Looking back, it's clear that the internal representation had changed from an 8-bit encoding to UTF-16 but I learned to be careful to "save as Word 95" every time from then on.
Yup, exactly this. And there would usually be an official plugin you could optionally install to read files from ~2 versions ago, presumably because businesses demanded it, but still wouldn't go back farther.
I can't think of any other program that removed the ability to open older versions of its own files. Kinda crazy.
There are two file extensions, but with every new word version there was new features, and thus new stuff that had to be represented in the saved file. If you only went forwards and didn't skip to many versions, and remembered to save the file again in the newer version you'd be fine. but as the mastodon thread says, anything from before a certain date won't open at all, and more complex documents from the 90s and early 00s might have surprising issues in modern word.
