[Picture] Amber shows up finally,"Glory December 7"?

This photo here caused quite some discussions among fans,many were doubtful of her future as a f(x)'s member since her legs injury as she failed to show up in f(x)'s recent projects.

This is the most recent photo we are able to find and she seems to have hinted something with "Glory December 7",what does it mean actually?Make a smart guess

source: baidu, blog .me /117083336