Amend 2020 return in 2021

Can I e-file an amended return for 2020 in 2021? If so how? I am in TT version for 2020 and when I try to transmit the amended return electronically it gives me errors saying dates have to be before 12/31/2020.  However I also see note in TT that says a change has been made to be able to electronically file prior year amended returns.  Am I missing something here or do I have to file by mail as only option?