This is very frustrating. All documentation states that I can e-file a 2021 return in 2023, except the software fails at the very last step. In my case, it's 04/14/2023 today and I'm unable to e-file a 2021 return because my signature date is not between 01/01/2022 and 12/31/2022. Changing the signature date to 12/31/2022 also fails with "e-file season closed" type message.
It's either a bug TurboTax is not willing to admit or fix, or just false advertisement. Very disappointed to see a just-in-case feature I've been counting on to flat out not work the first time I had to use it.
