Google has official releases new android 4.4 and this latest OS only available for Nexus 5. The new Android 4.4 KitKat also load with lot of new application such as keyboard, camera, Google Now, wallpaper and more.
This Android 4.4 Kitkat also support some other Android devices such as Galaxy S3, Note 2 , note 3 and more. But i am not sure when Samsung will releases this official Android 4.4. Without waiting the official update to test the Android 4.4 KitKat stock application, now the Android 4.4 Keyboard APK was extract from the Android 4.4 OS and was pack into apk. So, you can download Android 4.4 Keyboard APK and then manually install on your Galaxy S3 and Note 2.
Download Android 4.4 Keyboard APK: Link