Dont know if its just my problem, but dialog boxes created in 2017 or just saved in 2017 are not compatible with Diadem 2015 version. it throws an error "invalid file type" when trying to open them by scripts.
If its a feature, i recommend you to write it in release notes, i have read it and i didnt find a note about the incompability, which got me in small trouble on our production.