As of Alpha 7, it is now possible to change a prisoner's security category. This can be done by clicking on the prisoner and changing the appropriate setting in the menu that comes up.
A good way to keep prisoners from escaping is by surrounding your prison in a wall and using 2 solitary doors to keep them inside the new prison yard. Once you have Deployment researched, you can set up an 'airlock' at the entrance of the prison (a small area with one door to the inside, and one door to the outside) and set that area to Staff Only in the Deployment menu. This will prevent prisoners from going there, but doesn't prevent them from leaving the prison once they are released. If you put a metal detector at the entrance, you can help prevent prisoners arriving carrying metal contraband items, which could include a set of prison keys.
To stop the arrival of new prisoners, continuous intake must be off and all 3 prisoner categories must be off. To turn on/off the prisoner intake, go to the reports menu, the prisoners tab, and close all 3 levels.
Prisoners will arrive at the prison entrance restrained and unable to move on their own. A guard will then guide them to a free cell or when none is available to the holding cell. Their handcuffs will then be released and they will start following the daily routine as described in your regime.
When there is an unobstructed route to the border of the map they will attempt to escape. Guards will try to prevent them from doing this by beating them down.
Each prisoner is sentenced to a specific number of years. Each game day is actually one year of prison sentence. When a prisoner has served his sentence, he will be released and let out of the prison.
There are 3 different categories of prisoners. Each category has a different threat level. You can see the difference between High, Normal and Low by the Prisoners Clothing.
They will have less chance to try escape, engage in fighting and complain. Their outfit colour is grey. If a lot of other prisoners are fighting, then they will join in the fight.
They will try to escape when they have a chance and they will both engage in existing fights and start fights. Their prison uniform is orange. They will complain when needs are not met.
They tend to be more dangerous. Their prison uniform colour is red. They will always try to escape when their needs are not met, and they will always complain a lot when their needs are not met. They will start a riot by fighting other prisoners, and they will also attack staff without provocation.
There are also special prisoners, when they come they will have different colour outfit, such, black,blue,green etc. But when they will put in cells, they will be automatically given the appropriate colour uniform for their threat level.