In the Android root saga along the years we've seen many ups and downs relating to how root is achieved and how nearly every version of Android since 4.3 Jelly Bean has changed that method. For the uninitiated rooting is basically gaining administrator rights on your Android device, allowing you to modify any system file you choose. This gives you as the user the ability to theme your device, access additional features that the manufacturer didn't build in, and load custom ROMs to switch our your entire OS, among other goodies. As a result there are plenty of users out there that want root access and won't bother updating to a new phone until root access is achieved. Now it looks like the next Android update, Android 4.4.3, might be changing the way root is achieved once again.
If you've been a part of the Android rooting community for any amount of time you've no doubt heard of the developer Chainfire. He's a pretty legendary developer that's famous for the popular SuperSU app that regulates root permissions for individual apps, and has created a number of other root-based apps as well. Android 4.4.3 is set to introduce a lot of behind the scenes changes, some of which are involved in making Android as a platform more secure. This secure element within Android is called SELinux, and was introduced in Android 4.3, and has been continually strengthened in every release since then. As a result of making Android more secure there are now less loopholes than ever before to gain root access, and as a result less ways for nefarious apps to gain access to places they shouldn't be allowed.
Basically this new change in Android removes the old way of executing processes as super user (root), and to top that off the way processes could communicate with eachother in this manner has been removed as well. To make matters more complicated ART, the replacement for the old Dalvik runtime in versions of Android past, doesn't permit apps to run code they aren't allowed to, causing the whole OS to shut down to prevent security intrusions. Right now Chainfire has a new SuperSU build being made ready for Android 4.4.3 but is urging users that update to Android 4.4.3 to switch back to Dalvik until a better method can be concocted.