Train your clients and collaborators: "I will send you design_final.indd (v2025) and design_final.idml . If you are on an older version, open the IDML."

Unlike Word documents or PDFs, Adobe InDesign files ( .indd ) are complex database structures. They are not simple text and image containers. Converting a file from a newer version to an older one involves stripping out specific code and features that the older software doesn't understand.