From what some others and I myself have observed: From regular containers, if you don't have a Rare (blue) rarity item at or before container #14 or earlier, then the 15th will always be a Rare (blue) item. From Ultra containers, if you don't have an Epic (purple) rarity item at container #14 or earlier, then the 15th will always be an Epic (purple) item. I watched Mr. Akame open some Ultra containers earlier, he also tested if the x5 openings function like this, and it seemed to match what x15s would do (if the first two x5s had no purple or above, and the third x5's first 4 weren't purple, the last container from the third x5 would be purple). He didn't try it with regular containers, but it worked at least with Ultras, so I'd also assume it's the same with regular containers as well. To answer the question at hand, any given x15, whether it is Ultras or regulars, will in the very least give an item of the promised rarity once (so Rare/blue from regular and Epic/purple from Ultra containers). If it goes to the guaranteed on the very last container, it will always be whichever guaranteed rarity it is, depending on the type of container you open. From some experiences I'm fairly sure it will not be anything higher, unless you've had the guaranteed rarity earlier than the very last one, and even then it will not always go past the guaranteed rarity. I hope that answered the question.

The DM mode will have drones and ODs disabled so no Hornet ODs. Still gonna be a status augment spam fest most likely.

I have never personally really liked any of the special modes apart from a couple (such as the Smoky Wasp Short Bridge CTF, that one was actually enjoyable). Always dreaded the "Earn 20k crystals in the festive DM mode" missions, but I still do those for the ultras. Now I feel like this 5k battle score is gonna take even more time in the DM mode than before. I guess that was a tactical decision to change the mission to be battle score instead of crystals, now everyone has to play for longer and can't just get relief from premium. At least we won't have to suffer with the Hornet Booster/Viking Booster or Defender/Booster or Defender spam in general since drones and ODs are disabled but still, I somehow have a feeling already that if you aren't 9999 GS and especially if you don't have any cheesy augments to play with you just won't have a good time. Could be just me, or not, but I suppose the only way to find out is to see it tomorrow.

The magic of finding out things that weren't announced, am I right? I do agree that the OD deserved a bit of a buff, but to have a buff that wasn't announced only to have a nerf which IS ANNOUNCED is a bit interesting, don't you think.