Core Points - The IRS deadline for filing tax returns after an extension remains October 15, despite the ongoing government shutdown [4][2][1] - Taxpayers who requested an extension must still pay any taxes owed by April 15 to avoid penalties and interest [2][1] - The IRS has furloughed about half of its workforce due to the shutdown, which may lead to delays in taxpayer assistance [6][7][8] IRS Operations - The IRS continues to offer its Free File program for taxpayers with an adjusted gross income of $84,000 or less, providing free guided tax software [5] - Some customer service agents will remain on duty during the shutdown, but taxpayers may still face challenges in getting assistance [6][7] - The National Treasury Employees Union (NTEU) has warned that the shutdown could create a backlog of work and frustration for taxpayers [8]