E-filing 2018 return

[Stan4d00]

I am trying to e-file my client's 2018 tax return, but I'm receiving an error message that the e-filing window is closed for that year. My understanding was that we have 3 years from the date the original return was due, including extensions, to e-file a back return. Does anyone know what ProSeries allows for transmitting old returns? The FTB would much prefer to receive an e-filed copy, vs mailed, and I'd like to be able to do that.

Thanks!

[sjrcpa]

Current and prior 2 years can be efiled through the software. 2021, 2020, and 2019.

[dkh]

IRS allows for filing for a refund - three years from due date including extensions -  but that does not mean efling is allowed.    2018 will need to be mailed