PeopleSoft FSCM 9.2 Supplier Contracts-DocuSign and PDFs

Hi Knowledgeable Folks, Another Supplier Contract-Document Management question.

I was under the impression that the PeopleSoft/DocuSign integration was unable to support PDF format, that the document had to be essentially XML. However, some of our users have been able to import PDFs and the Prepare and Route for e-Signature button does appear. In our test environment I followed through with this and was able to drag and drop a signature onto a signature line.

Note that we upgraded to Image 30 from Image 19 in November 2019. Was this capability always available? Or did the ability to DocuSign a PDF from PeopleSoft become available somewhere between Image 19 and 30?