Had a small problem after the OS update this morning with the scale of my second display. While it would recognize the ability for the monitor to do 1920x1080; the horizontal scaling of the second display was much narrower than the available pixel space on screen.
After restarting and resetting PRAM (control, command, p, r) I disconnected the cable from the back of the mac and connected it again. This caused the screen to reset, the monitor to be recognized as something other than a “Vanilla VGA Monitor” and the squeezing was gone.
All-in-all a really simple upgrade path. Just this one issue.