Upload my old DS 160 form while filling out new one - pdf error

I want to upload my old DS 160 form while filling out new one.
There is an option UPLOAD APPLICATION.

When i am trying to upload pdf file, its giving me error that unknown file format
Any idea? How to do it?
Thanks

You cannot upload an old DS160 pdf file.

As far as i know, you have to create a new DS160 every time for new visa application.