Updated for Tax Year 2014. OVERVIEW. Now that you've bought up to six extra months by filing an income tax extension, you might be wondering what you need to do between now and your new 2014 tax return deadline of October 15, 2015.Weâve addressed some of the most common questions below:VERVIEW. Now that you've bought up to six extra months by filing an income tax extension, you might be wondering what you need to do between now and your new 2014 tax return deadline of October 15, 2015. Weâve addressed some of the most common questions below: