A little extra security is added to your Android as lock screen widgets can be disabled in the system settings
Kit Kat brings a change to one of the features from Jelly Bean that everyone has an opinion about — the lock screen widgets. On one hand, they offer a bit of information from any application that supports them (quite a lengthy list) and can be great for things like music controls or messages. On the other hand, they were kind of clunky, required at least as much interaction as unlocking the phone, and for many, seemed like a unnecessary security risk, where anyone could pick up your phone and add widgets for access to private information.
Lock screen widgets are still present in Kit Kat, but you'll need to enable them in your settings should you wish to use them. Nestled appropriately under the "Security" section of the device settings, you'll see a line item for Enable widgets. While you're not really told as much — Google often has "issues" communicating well — the group of settings there for Owner information, Enable widgets, and Screen lock all have to do with the lock screen. An Android pro would figure it out, but not everyone's an Android pro.
Anyhoo, check the box next to Enable widgets and you'll be able to add lock screen widgets in the same way you did for Jelly Bean devices. Leave it unchecked, and you'll not be able to. If it's unchecked, and you're using a secure lock method, nobody else will be able to, either. This is how a feature like this should be offered. Nicely done, Google.