Quote Originally Posted by Ryuko View Post
After defeating Twintania, you are led to a new quest (not going to be more specific than that... spoilers!), so yes, you only REALLY have to beat it once because it unlocks that new quest for you. There is nothing available after completing that quest for current players, so I assume the quest for 6-9 will be a continuation of that one. I would advise doing everything you can to beat Twintania before 2.2 so you can immediately jump into the fray of 6-9.
Yep, just recently defeated Twintania, and that quest in the Waking Sands is kinda the last thing you do after defeating Turn 5. Like Ryuko said, I'm sure that's the pre-req quest you need before they release the next step to unlock 6-9. But I agree, it would be nice to get as many people clears on T5 as possible so more people can start T6-9, and since it will be a lockout, that means the few people around for it will be even more limited.