Nothing says A Realm Reborn like making the jump to next-gen.
Hergen Thaens, Square Enix's community project manager, has recently posted on the PlayStation Blog to let you know that if you played Final Fantasy XIV: A Realm Reborn on PlayStation 3, you will be able to upgrade to the PlayStation 4 version for free. Just as long as you have logged into the PS3 version once, you will be able to upgrade until the end of the year. All players should be aware that once you upgrade your FFXIV account to PS4, you will no longer be able to access the PS3 version of your game ever again (you would have to use a different account).
Starting on April 11, FFXIV players on PS3 just need to log into the MogStation with their Square Enix account and go to the account services page to upgrade to the PS4 version. After a few steps and confirming your upgrade, you should receive a promotional code to download FFXIV for PS4 from the PlayStation Store.