One of the big changes in Android 4.4 was the addition of ART, a new runtime compiler for apps that was set to replace the aging Dalvik. ART was introduced as an experimental feature in Android’s developer options, and it came with its own set of problems. Even though ART was quite a bit faster than Dalvik, many apps didn’t play nice with the new compiler, and even though several apps have been updated to be able to function with it, it’s still not the norm for most apps. Of course, since ART was an experimental feature, it wasn’t a big deal that some apps didn’t work with it. Considering that not too many devices even have access to Android 4.4, it’s really not much of an issue at all.