The Android 4.4.4 KitKat update would be arriving to the handset via Over The Air, where it will be a rather sizeable 346MB, so it is highly recommended that your handset has at least half of its battery life left, not to mention being connected to a decent Wi-Fi network to make things as painless as possible. Other than that, there ought not be any kind of major changes, as Android 4.4.3 KitKat would have already taken care of the bug fixes, while Android 4.4.4 KitKat would target more on security issues.
Do be patient if you have yet to receive the Android 4.4.4 KitKat update, as it might take some time considering the rollout is done in stages.