Can I use my original offer letter to renew?

When I applied for my TN at the border last year, I presented my ID and diploma and:

1-Letter to the NAFTA examiner
2-Original Job offer letter

I updated my NAFTA letter by updating the date. Can I just keep the original job offer letter as is or do they have to write me up a new one?

I had to use a new letter each time I renewed. As the TN visa is only valid for one year, my agency had to acknowledge that their offer was only valid for the length of the visa, so each year they put into writing that they were willing to keep me on.

Good luck.