Every few months the Final Fantasy XI drops a massive update to the game, and we were due for another one this month. The December Update saw updates and tweaks to elements of the title across the board, with new missions and quests centered in the Wings of the Goddess expansion areas one of the update's biggest selling points. The other big component is the introduction of the "Fields of Valor" system. Fields of Valor will allow players to take on 'training regimes', targetted missions to slay a number of specific enemies in a specified amount of time. Every day, one training mission will be assigned and the rewards for completing it include experience, gil, and points within the new Fields of Valor system. Points may eventually be turned in for fun bennies. Other new game elements include: dropped treasure chests for extra loot (both temporary and permanent), some quality-of-life additions to the Campaign system, minor tweaks to the Level Sync system, and a number of changes to in-game items. There's an enormous list of changes, as there is every time they do one of these, and you can find the full list of game updates on the official site.
Update: Fixed to reflect that the changes have already gone live.