How much past october 16, 2017 can you still efile with Turbo tax? When does turbo tax shut down for 2016 individual filers?

[DoninGA]

For the 2016 online editions -

October 16, 2017 at 11:59:59 PM local time to the customer- The final deadline to E-file your return for this tax year and be considered “on time” (assuming you filed an extension).

October 22, 2017 at 3 AM PST- Last day to fix rejected returns and not incur additional penalties or interest (again assuming an extension was filed and accepted)

October 26, 2017 at 3 PM PST- Customers will no longer be able to sign into TurboTax Online itself, but still can access their MyTurboTax.