Ok, I have an upcoming writing project and decided: why not? So I made my $19.99 purchase for a good cause. But Hemingway is a bit of an island. Once you have

Ok, I have an upcoming writing project and decided: why not? So I made my $19.99 purchase for a good cause. But Hemingway is a bit of an island. Once you have a document ready, how do you use that creation? You can export in .doc format (good). But one can only import a .docx format. Why is that?