TN Visa Support Letter Original Signature Required?

Hi everyone,

I am preparing a support letter for my employer (startup) who is having me (Canadian) enter the US on a TN work visa.

I had a quick question regarding the TN support letter:

I've read online that an original ink signature on the support letter is required. Is this true? Or would a digital signature be sufficient?

Would prefer not to have to go to the trouble of mailing an original copy, but if it is required then it will need to be done.

Does anyone have any personal experience on whether an original signature was required?

Thanks in advance!

Non Immigrant and Immigrant Visas