Google announced Android 4.4 KitKat yesterday. You can read about the changes and improvements included in the new Android version here. Today they released a new version of the Android SDK and both ADB and Fastboot were updated.
I just published a new custom installer. This time is for installing the latest versions of Android’s ADB and Fastboot, which are needed to flash recoveries and ROMs, among other things. Normally, you would need to search for these tools if you don’t want to install the whole Android SDK.