I'm filing an estate income tax return for my mother who died July 2017. Do I need to file a return by April 17th or is it after the fiscal year ends (i.e., June 30th)?

Tried to file using TT Business but the return was rejected saying that the Tax Period End date must be less than the Received date.  I don't see an option to select the Calendar Year of 2017 versus the TT plugged Fiscal Year dates of July 1, 2017 to June 30, 2018.  Also, if using the Fiscal Year dates how do I handle estate income from 2018 that I won't receive statements for until next year (i.e., I have 1099s for 2017 for the estate but nothing that would cover 2018 yet).