I am aware that this is a minor feature request at the moment but in the long run I believe it will be necessary.
Now that there are two very distinct Doricos versions and it will surely not stop there, would it be possible to have a hint when you open a project telling whith which version the file has been created?
It would be also great if the file would be opened and converted to the new format with a new title and if the old file could say untouched.
New added or improved features may considerably change the look of a score and this is not always wanted.
At the moment, testing Dorico 2, I manually add a "-d2"suffix to the file name so it’s not a great deal but at some point in the distant future it will be more and more difficult to remember with which version a file has been created.