I am in the process of collecting my recommendation letters and so far has 4 recommendations were submitted as PDFs. Since I’ve started collecting the recommendations before the January update, I didn’t ask my recommender to use DocuSign. Reading the requirements it doesn’t seem to be mandatory but just want to make sure.
* Letters of recommendation can be created using a digital signature service (such as DocuSign or similar service), enabling the inclusion of the document log file that clearly indicates the letter’s author and signature originated from a different IP address to the applicant. Letters must uploaded on Tech Nation's Application Platform.