I need to send my Indesign CC 2015 file to another colegue with CS5.
Save as InDesign CS4 or later (IDML) or package the entire project making sure to create the IDML file as well.
Be aware that text will probably reflow and any new features will be lost or badly mangled.
If you’re intending this for a roundtrip workflow you are making a major mistake.
Retrieving data ...