Linking of Aadhaar with PAN

Dear Colleagues,
Need one small clarification,

My Grand mother is 90 Years Old. She does have Aadhaar number as well as PAN number.  She never filed ITR. So need guidance on whether  she is required to  link their Aadhaar number with pan  or She is exempted from mandatory linking of pan  with Aadhaar as per exemption notification 37/2017..