I kept receiving the error message "too many guards posted". I thought it was part of the update, but I've come to the conclusion that it is a bug(possibly).
At first I figured I would just remove guards from another post and switch them. Well, that didnt work and I can not place guards back at original post.
Then I figured maybe I need more guards. So after hiring more guards I could now deploy more to a post. But after a while the error came back and this no longer helped.
Finally, I noticed that my prison info had 252 guards posted, BUT I only have 135 hired!
So I found out that if you delete a room with guards still deployed in the room they stay deployed even though it is not shown, and it limits the amount of guard deployments.