I have a client that wishes to have the Revit 2014 file reverted back to 2013. I was told that I could send the 2014 file to Autodesk and they would be able to revert it back to 2013. Is this true? Thanks for your help!
Export to IFC, then import the IFC file into the previous version of Revit.
WARNING: THERE WILL BE SIGNIFICANT ERRORS. DO THIS AT YOUR OWN RISK!