-There are new achievements for you to unlock.
-A message will appear at the bottom of the screen when you unlock something. Steam will offically update with the achievements completed once you exit the game.
Achievements Added 8 /16 / 2016
Build and release context
Steam update times within 24 hours of this post. Matching dates do not confirm which build it describes.
Build 1283325 · public branch
Steam updated · First observed