Digital signatures with different versions of Reader

Question

I have created a form which requires a digital signature for approval. Typically, an employee will complete the form in Reader and forward it to a supervisor for approval. The supervisor needs to sign it digitally and forward it to me.
The issue we are having is with those employees who are completing the form in Reader and the supervisor (or someone thereafter) has a more updated version of Reader and cannot sign the document. What can we do to stop this from happening? There is no practical way to keep everyone on the same version of Reader. We will have many more forms which require a signature, and we need this issue resolved. (I am using Adobe Acrobat 9 Pro to create the forms.)
Also, is there a way to verify the digital signature without using a third-party source? At this point, we know anyone can create a digital signature using someone's hand-written signature they found on another paper and we would like to prevent this from happening. We need to validate the person who used the digital signature is really that person.
Any help is appreciated! Thank you!

Answer 1

If you are creating your forms in Acrobat 9 Pro. and then Reader-enabling them for digital signatures, then recipients of the form will need to use at least version 8 of the Adobe Reader. Also, you'll need to do a few things during the authoring stage of your form, if your form changes by role (i.e., additional data is entered, annotations, or multiple signatures). Mainly you'll need to use a certification sig. for the first signature and set permitted changes after certifying.
You can find a lot more detail on best practices on developing forms for multiple signatures in the Digital Signature User Guide at:
http://www.adobe.com/devnet/acrobat/pdfs/acrobat_digsig_userguide_90.pdf
The guide also explains how to validate documents (authenticity validation and document integrity validation).