The shutdown is coming earlier this year in order to make preparations for reprogramming the 2015 tax season. Note that acknowledgments may be delayed slightly, so you will want to watch these dates to make sure you receive them before they are no longer available.
Through November 21st: Proceed E-filing individual returns for tax years 2013, 2012, and 2011.
November 21st: Electronic Filing Center stops sending 1040 E-files to IRS at 6:00pm PST. This allows time for state return processing and ack retrieval.
November 22nd: IRS shuts down individual E-file at noon. Acks not received by the ERO before noon will become available again when efile opens in 2015.
Through December 23rd: Proceed E-filing business returns for tax years 2013, 2012, and 2011.
When IRS opens business efile in 2015, returns for 2014, 2013, and 2012 can be submitted.
How will this affect the tax season?
As of now there is a delay expected, however it is too early to tell how long it will last or exactly when the filing season will begin. A big factor in this will be determined when congress decides the ruling on the expired tax provisions.
IRS Commissioner John Koskinen tells tax professionals to expect a long wait when calling the IRS for assistance this year. Only an estimated 53% of calls will get through and the other 47% will remain unanswered. There are several causes for this prediction including the complications from the Affordable Care Act and the primary reason according to the IRS is the $341 million cut in their budget and no funding to implement the Affordable Care Act.