InDesign documents are specific to the version in which they were created. Documents can not be opened directly in older versions of InDesign.
Opening InDesign CC 2017 Documents with InDesign CS6 and InDesign CC 2015
Users with InDesign CS6 and above who also have access to Creative Cloud services can utilize the Simple Saveback service to open documents created in a higher version of InDesign CC.
To open a CC document in CS6, follow these steps:
Step1. Confirm that you are running the most recent version of InDesign CS6.
Step2. Confirm that all updates have been installed.
Step3. In InDesign CS 6, open the CC 2017 document.
Step4. When prompted to convert the document, click Convert.
Opening InDesign CC 2017 Documents with InDesign CS 5.5 or Earlier
To open an InDesign CC document in CS5.5 and below, it is necessary to save the CC document as InDesign Markup Language (IDML). Also, make sure that the computer running InDesign CS5.5 or below has been updated with the necessary plug-ins so that it can open the exported IDML file.To save a CC document to the IDML format, follow these steps:
Step1. Confirm that InDesign CS 5.5 has been updated and includes the necessary plug-ins.
Step2. In InDesign CC, choose File > Save As.
Step3. From-the Save as type options, choose InDesign Markup (IDML).
Step4. Click Save.