All current Final Fantasy XIV players will have a chance to try out the planned November update. Square Enix is extending the Final Fantasy XIV trial period for another 30 days.
Anyone who registers for an account and creates a character by November 19 is eligible for the an extra 30 days of Eorzea. This includes current players, even those who already received a trial extension in October.
The November update which adds new guildleves, an auction search feature, and dozens of other changes has a tentative release date of November 25.