November 14th. Why? http://na.finalfantasyxiv.com/pr/blog/000517.html

This special FATE is scheduled to go live on November 14, a week before the Japanese release of LIGHTNING RETURNS: FFXIII! Hope you're all prepared to unravel the secrets of Lightning in Eorzea!

As a special treat, you can take a look at the LIGHTNING RETURNS side of the collaboration to see how Eorzea bleeds into Lightning's world!
I could be wrong though...