Alongside of its major "4.2/4.3" and so on updates that bring new raid and dungeon content on top of hundreds of quality of life updates, the Final Fantasy XIV team also provides mini-patches that add in anything from quests to job alterations.
This time fan-favorite Hildibrand gets a mini narrative continuation, but the big draw is most definitely "The Forbidden Land," Eureka, a whole new area for players to dive into and earn artifact gear from. Obtained from Rhalgr's Reach (X:9.8 Y:12.5) after you've completed the story, the new questline will send you into Eureka, an instanced area of "up to 144 players" that syncs to item level 300. From then on you can enter by speaking to an NPC in Kugane (X:8.5 Y:14.2), where there is a massive focus on getting a party together (you can invite inside of the instance, something that's not typically possible), as well as change jobs at a specific port, and unlock the ability to ride mounts.
The entire zone is dictated by experience points that contribute to your "Elemental Level," which is earned by defeating enemies and lost after being KO-ed past elemental level six. Magicite and an elemental affinity system further complicate things. As a reward you'll unlock protean crystals, which enhance your gear by way of the NPC Gerolt, located in Eureka.
The only thing left is to give it a go and see if it's worth playing beyond the first initial honeymoon week!
Patch 4.25 notes [Final Fantasy XIV]