Hi jebs_girl and welcome to our community
No version of RoboHelp HTML has ever been backward compatible
with earlier versions. Once you go with the new version, it makes
changes to your project that prevent the older version from opening
it up.
Now that's not to say it can't be done. For years I've been
able to open older projects in a variety of ways. But I believe
version 7 presents a new wrinkle here. I've tried opening a project
in 7 then opening in the older version. Seems fine, but the older
version always tosses an error message and closes RoboHelp when you
close the project. We still don't know why.
Cheers... Rick