There are no extensions beyond October 16 unless you are in one of the federally declared disaster areas where special relief is being provided. You can still file after October 16, but you are filing late. If you are getting a refund, there is no penalty for filing late. You cannot e-file after October 16. You have to print your tax return and file it by mail.
TurboTax Online will not be available after October 16, even for disaster areas. To file after that date you have to use the CD or download TurboTax software.
Links to IRS information about disaster relief:
https://www.irs.gov/newsroom/tax-relief-in-disaster-situations
