Disney has officially changed it's dining policy regarding restaurant reservations. Instead of a 180 days, the booking window has been scaled back to 90 days as of Dec 23rd. This also applies to recreation and tour reservations as well. The only exception will be Cirque du Soleil which will continue to accept reservations up to 180 days in advance.
Existing dining reservations are not impacted by this change, and those traveling on a 'Grand Gatherings' package will be able to book 180 days out.