Prison Architect. The biggest inclusions in the patch is a new "anger model" and prison riot system.
According to the developer, "The system for determining when prisoners become angry and misbehave has been totally overhauled. There is now a Thermometer which represents the "danger level" of your prison. A high "temperature" will lead to fights. All prisoners have a "boiling point", which represents the temperature at which they will kick off. Max sec prisoners will tend to have a lower boiling point, meaning they will kick off earlier."
Factors that will increase the angel level of a prison include being locked up for no reason, the presence of riot police and recent deaths, while things that will lower it include good treatment, presence of reguard prison guards and recent punishment used as a deterrent.
Riots will occur when the boiling point is passed, and will create a vicious cycle: riots cause more anger, more anger causes more rioting, and so on. Rioting prisoners will claim and caputre their own cell block, and will spread the riot to neighboring blocks. Guards and staff will avoid captured prison blocks, and must be forcefully instructed to intervene.
During a riot, players will have to call in Riot Police, heavily armored guards, as well as Paramedics. Again, Riot Police will only fan the flames with their presence, requiring them to come down hard on prisoners to quell the riot.
Check out the 20 minute Update 10 trailer in the video below.