InDesign will process the markup and open it as an document.
To convert an Adobe InDesign file to a version that older software can open, you must export it to the IDML (InDesign Markup Language) Standard Conversion Steps how to convert indesign file to older version link
To convert an InDesign file to a version that can be opened in an older release, you must export it as an file . This format is compatible with InDesign CS4 and later . Standard Conversion (IDML) Open your document in the newer version of InDesign . Go to File > Export . InDesign will process the markup and open it as an document
