The Sims Team has updated their Gallery sliders that you can find in TS4 main menu, and along with that update there’s a hidden slider that’s yet to be revealed.
Inside a .spotlight package file that can be found in The Sims 4 save game files, there’s a new paragraph that states the following:
COMING JULY 9
GAME UPDATE: NEW WAYS TO BUILD
We’ll be adding half walls, locked doors and more in the latest game update, free to all players!* (*Requires internet connection for installation)