Ah sorry, you missunderstood, its not a upgrade as in an old/new screen, its an upgrade you make ingame. (Screenshot description has been edited to make it more clear)
All rooms in the player characters' hideout now start out abandoned/storage only and can be upgraded to a later stage using resources earned in the town building system.
The same now applies for the other rooms too. (bar, library, bath, medic)
Edit: Errors at the upper corners have been fixed ingame.