Yea unfortunately I do know what causes this , Adobe is a terrible company and deserve to be put in a dark room filled with terrible things, they like to prevent older versions of substance painter from opening projects saved on newer versions of their software. Thus making their older software out of date. To get access to the new substance file you need to update your substance painter.
No worries! It used to give an error message saying it was the wrong version hence why i got confused haha.Updated my substance painter and it works! Im looking for the tail in the substance painter file but i cant seem to find it, is it a somewhere else? (Thanks for the quick response, loving the avatar!)