The ARMS Twitter account just posted another update containing the image above. It certainly looks like a new stage, doesn’t it?
The tweet has Biff talking about being on vacation and hearing that there is a fighter around here. He also mentions the sweet scent and exoticism in the air.
Everything points to this being related to a new fighter, who will likely be accompanied by a new stage as well. It does line up with what we heard from the datamine last week.