Prisoners working in the laundry will occasionally try to steal five uniforms to make the rope, and may trade it with other prisoners. If you don't notice the missing stock or find the rope stashed away, then they'll head out to the nearest wall, fling the rope over, and make their escape. You'll have to tell a workman to get it down sharpish, because other prisoners can follow them.
Strong prisoners now don't even need a rope to escape: then can straight-up climb over fences to get out.
But you've also got a new tool to help keep prisoners in line: the roll call. You can do it at anytime—3am seems best—and it will wake up all prisoners and force them to stand in their cell doorway. If they're late, it's a dead giveaway that they've been tunneling underground, and nearby guards (or your own watchful eyes) will notice.
The update also adds new graphs for your to track the performance of your prison over time, improves mod support and fixes bugs. You can read the patch notes here, and watch developer Introversion Software talk through the changes in the video above.