Since @Just-Lisa-Now-  resurrected this thread (thanks...) 

A quick question IF anyone knows off-hand - can this election be made on a delinquent 2020 return? 

OR, an an amended return?

I didn't have a single client who did this in 2020, NOW I have a long lost client that has re-appeared.

TIA - I'll do my own research (Pub 17 anyone 😉 if no one knows the answer off the top of your head.