Preserving document format using newer release

I make a habit of creating a ZIP of my document directory prior to upgrading. This preserves the ability to edit the docs in the previous version, though obviously you do not get changes that were made in the newer version.

Bob's MIF solution is also a good one.

-Matt

>>...but it looks like the files get upgraded to the newer format when using the standard Save / Save All...

I would not expect any program that uses unique file formats to act differently. 

You could of course, before opening, simply copy the files using the file manager. Or does this not do something you need done?

I got in the habit, years ago, of saving every released project in MIF (largely because it was never clear what FM versions any outside translators would be using). Even when you open an old .fm/.book in a later FM, it won't touch the MIFs unless you do so deliberately.