With release of Windows Server 2016, microsoft announced End of life (EOL) for Windows Server 2012.
Windows Server 2012 R2 Standard was released on 25-11-2013. Mainstream support end date is 09-10-2018.
The Mainstream and Extended Support dates for Windows Server 2012 have been extended for customers, to align with the standard lifecycle transition timeline.
The Lifecycle Policy for Windows Server 2012 states that Mainstream Support will be provided for five years, or for two years after the successor product (N+1, where N=product version) is released, whichever is longer. Microsoft will also provide Extended Support for the five years following Mainstream Support or for two years after the second successor product (N+2) is released, whichever is longer.
Due to the timing of the release of Windows Server 2016, an extension was required. The newly published October Mainstream and Extended end dates are correct. You can find the new dates here.