@DaveF1006
The old notice you referenced says you have until August 31, 2020 to do something.
It is now April 2022.
@Caseyblue
Please see Worksheet 5 Line 4 in the Instructions for form 8915-F at irs.gov.
https://www.irs.gov/pub/irs-pdf/i8915f.pdf
Also Instructions, Line 14.
If you are going to delay, file Form 4868
