During today's live Final Fantasy XIV: A Realm Reborn Letter from the Producer, Naoki Yoshida confirmed that phase 4 of the Beta Test would run from August 17 through August 19 as an open beta. For gamers who took part in phase 3, they will have access starting one day earlier on August 16. Unless some major bugs are introduced this phase, players will be able to transfer character data into the full version when it launches. There will be a cap of level 20 during this beta phase, so that certain content will be saved for the official launch.
Other new content being made available in phase 4 includes the Arcanist class and a screenshot function added to the PlayStation 3 version. The Arcanist class will be DPS (damage per second) focused and can summon pets like Carbuncle to assist in combat. These pets will be able to fight on their own using a system similar to Final Fantasy XII's gambit system, but can be directly controlled as well. The Arcanist is the base class for the Summoner and Scholar jobs.
Those who have pre-ordered Final Fantasy XIV: A Realm Reborn will receive early access to the game starting on August 24. Please read the entire translated Letter from the Producer for more details about the world transfers and other services coming when the game launches on Aug. 27.