The new patch brings Frontline: Onsal Hakair to the game, a new PvP map and ruleset for players to fight on. Per the press release:
This new frontline map and ruleset teams up each of Eorzea’s grand companies with a tribe of Azim Steppe as they fight for control of territory in this grand demonstration of martial prowess. Each team will work to capture ‘Oovo,’ bases which earn a team points while under their control—the first team to accumulate the required points will be declared the winner.
Additionally, Blue Mage players will find themselves with more to do as patch 5.15 brings with it new content for the class. In addition to the content, Blue Mage players will get an increase in level cap, from 50 to 60 and can take part in new job quests, learn new spells and more. Additionally, Blue Mages will be able to participate in the Blue Mage Log, allowing players to form up parties and take on various dungeons and trials using only Blue Magic.
You can check out the full Patch 5.15 notes on the official Final Fantasy XIV website today.