Prison Architect developers Introversion Software joke in their latest update that the dev team is now "more like half a million." As well as an amusing way to introduce the changes to their mod system, which is now much more robust and capable of adding almost anything to the game, it's also sort of true. Their massive, ever-growing userbase will now add anything they can imagine, for better or worse, and folks will balance out what they want themselves. Others will improve the systems already there or build collections of mods that interact particularly well. Sit back, Introversion, you're basically surplus to requirements now.
On top of the new tools, Introversion have also added Confidential Informants who can be coerced into giving up information about their fellow prisoners. As you use this information it will raise suspicion of the snitch which, if it reaches a critical level, will lead to their bloody murder. It's an interesting dynamic that will force you to pick your battles, alcohol drops going unpunished so you can catch the guys tunnelling out or bringing in weapons. There's still balancing to be done, as it's a very powerful tool if you're uncaring as to what happens to the prisoner.
There's also a series of smaller bug fixes and additions, listed in the update post. The video above's a long 'un, but I'd recommend checking it out if you have the time as they show off the new systems and how mods are made in depth. There's a relatively simple to use tool bridging the gap between what you're wanting to do and the coding of the game. It's supported by LUA, a scripting language which I'm most familiar with from WoW interface modding, which is again pretty simple to learn.
You can grab access to Prison Architect, as well as all future builds, via Steam or the website for £20. It's ostensibly still in 'alpha' despite the remarkable number of features and possibilities, mostly due to bugs, regular updates and a lack of polish.