https://proconnect.intuit.com/community/individual/help/2019-e-file-start-and-stop-dates-for-federal...

"Can I e-file prior year business returns?

Yes, you can e-file the currently due tax year and two prior years (after the IRS opens e-file for the current tax season). For example, once the IRS has opened e-filing for tax year 2020 returns, you can also e-file 2019 and 2018 business returns. Extension filings are only available for the currently due tax year."