I had the same concern right after buying tickets. Here's arreply I got from support:
Thank you for contacting the Square Enix Support Centre.

We are sorry to hear that you are having issues with the FINAL FANTASY XIV Fan Fest.* The email contained incorrect information and was updated shortly after the emails went out.* The correct dates are listed on the website at http://ffxiv-fanfest.com/eu and it is the 18th-19th of February 2017

We apologise for any inconvenience caused but if there is anything else we can do for you please do not hesitate to contact us again.

Kind regards,

The Square Enix Support Centre team