Automatic update of content without DITA

Yes. If for instance you have a document with a mixture of text which is always the same and some texts which will be updated, you can have the last ones - as separate fm files. Then you import these files into the main document as referenced files. They will appear in your main document as large selectable textblocks and when you click them, you can open the source files. As they are manageable as links you can change the source documents and have them update in all the documents where they are used. With a little planning this is a good way to put together large books.