That is exactly the opposition of what you are trying to tell us.
You have Adobe CS6, version 8.x.
You get a file from someone else, who has Adobe CC 2014, version 10.x.
You are trying to open that file on your computer.
But because that file was created in a later version, you get this message.
Either ask to get an IDML file (with a PDF), tell them, they should go to File > Package… and check IDML and PDF export.
Better would be, if you also subscribe to the Creative Cloud to be up to date with the latest version.
But what you should do anyway, update your InDesign CS6, as there are updates available which will correct this error message, as from CS7 upwards no CS exists anymore.