Two new outfits were added, one from Roxanne the other from Hard mode Raven on Boss Challenge. Someone on reddit found a glitch that will let you cheeze HM Raven by giving you the abilities of 4 different exospines for Boss Challenges and double stacking defensive %s so that when you use a potion your melee defense is over 100% and her slashes literally will not touch you.
1) Load in the game and equip Recovery Mk1 spine, Protection Mk1 spine, Melee Protection Gear 18% + 15% + 12% and Protection Gear 12%. Save at a camp, pause and exit to title.
2) Enter Boss Challenge and fight on any boss with settings from Last Played Slot, pause and change your exospines to Recovery Mk2 and Protection Mk2 then defeat it and exit to title.
3) Load back into the game and immediately save, pause and exit to title screen.
4) Enter Boss Challenge again, select HM Raven or whatever fight you wish, choose Last Played Slot settings again. You will now have the stats and effects from all 4 exospines. Remember to use a potion to raise defense to the max.