Problem with Signatures

I upgraded a user to Acrobat DC.  Other people in the department have Acrobat X.  They all need to review documents and note that by attaching signatures with a date/timestamp.  These are just internal docs and do NOT need to be certificated or legal....just noted.

Acrobat DC will allow the user to sign a new document, but, not a document that was signed by others in Acrobat X.  Downgraded the user to Acrobat X....still not behaving as it should or as expected.

Is there a way to make DC compatible with X and just use simple, non certified, signatures???  (compatibility mode??)