I thought my physical keyboard and soft keys weren't lighting up after the update, but I think I figured something out.
Before the update, the physical keyboard lit up every time it slid out. Also the soft keys lit up whenever I used them, and they also lit up during the 5 seconds the screen dims right before the auto screen shut off kicks in.
After the update, neither the keyboard or the soft keys light up if I'm in a bright room. However, if I go into a dark room, they turn on after about 2-3 seconds. I think their settings have been changed to minimize how often they turn on in order to save battery power. I wonder if this was one of the battery saving strategies implemented in the update.