We don’t yet know when Final Fantasy XIV’s patch 5.3 will arrive; while the team has said there will be a delay, a release date has not yet been announced. What we do know is that you’ll have time to chase some gewgaws along the way with the latest Moogle Treasure Trove event, starting on May 18th and lasting until the patch maintenance for 5.3. And that means a pile of special tomestones for clearing dungeons, as before… but that list of dungeons has also changed.
While Praetorium, Castrum Meridianum, Aurum Vale, and so forth are still on the list, you won’t earn more Irregular Tomestones of Law (this event’s currency) through the Crystal Tower series; instead, you’ll earn them in the Return to Ivalice raid series (Rabanastre, Ridorana, and Orbonne). You can then exchange those tomestones for various mounts, riding maps, or the signature new reward of a mameshiba neckerchief. So you’ll have a little time to get yourself some rewards by running back through older content.Source: Official Site