Square Enix has detailed the changes coming in Patch 1.20, which is expected to hit live servers later this week. The team has released a full set of patch notes, which you can check out at the URL below.
Perhaps the most notable update is the announcement that players are going to be able to move further up into ranks of the Grand Companies, as Square unlocks those new ranks in Patch 1.20. The highest rank attainable is now Seargent Third Class. Alongside the patch notes comes a preview of the Moogle king of legend, the Good King Moggle Mog XII which is embedded above.
Take a look at a snippet from the patch notes below (click to enlarge):
For more on Patch 1.20, coming soon to Final Fantasy XIV, you can visit the full patch notes at http://forum.square-enix.com/.