Just found out that CRA has created a new standardized authorization form for Non-Resident, replacing the letter that was used before. The new form is called NR95, see link below
Since my firm handles a lot of NR, unfortunately, this becomes a mess for us as the CRA agent told me that letters that were sent recently may not be processed. Interested in hearing any peer advise on this issue.
Anyhow, I hope that tax cycle will implement this form in the near future.