Set 6 will appear on the Server after maintenance. It should show up in treasure battles (and your checklist) immediately. When I get into work I'll put up the Shop Items and Lottery, and then I'll set about making sure Set 6 shows up everywhere it's supposed to, like LEVEL UPS. So just to be safe, don't level up to a card level until I post on the Main Page saying it's all good.
"Scissors are overpowered. Rock is fine." -Paper