From The Lodestone:
Schedule:FINAL FANTASY XIV will celebrate its four-year anniversary on August 27, 2017, and in honor of this momentous occasion, we’ll be hosting a special 14-hour broadcast!
Peruse the full schedule and guest line-up.
Notably, the Live Letter (possibly dropping info for 4.1) is included in the program, at a reasonable hour for once (as long as you live on the US West coast).