in the version of InDesign it was originally created in (or any version newer than the file itself). Go to File > Export (or File > Save As in some versions). In the format dropdown menu, select InDesign Markup (IDML) . Click Save .
Leo leaned back in his chair. He knew that in the world of design, the art was only half the battle; knowing how to speak the language of older machines was the other half. 🛠️ Step-by-Step Technical Guide how to convert indesign file to older version