Square Enix just posted the following preliminary patch notes on the official Final Fantasy XIV website:
June 23, 2015 marks the release of our first expansion, FINAL FANTASY XIV: Heavensward, and it’s only days away! With players eager to dive into new adventures at the start of Early Access on Friday, June 19, it gives us great pleasure to release the patch notes for the 3.0 update!
At long last players can continue the main scenario in Ishgard, the isolationist nation engaged in a thousand-year conflict with the dragons. Whether you take to the skies on your flying mount to explore new areas, hone your skills as a dark knight, machinist or an astrologian, or dive straight into myriad new dungeons and trials, there is much to do in this exciting new addition to FINAL FANTASY XIV. A Realm Reborn will also receive a host of updates and new system features including DirectX 11 support, additional loot rules and Duty Finder settings, and more!
Only players with early access can play newly added content prior to the official release on Tuesday, June 23, 2015. However, all players will have access to updates affecting A Realm Reborn.
For the full details, read on.