As always, you will get a notification on your Google Play edition device once the update is available for you. As software updates are released in batches, it might take some time to reach your device. You can also manually look for the update by going to Settings > About Phone/ Tablet > Software update > Check Now.
According to Google, the Android 4.4.3 update includes stability improvements and bug-fixes.
To remind you, Android 4.4.3 was originally released on June 2 and apart from GPe devices, the update has just been rolled-out to Nexus devices (many users are still waiting for OTA) and T-Mobile Moto X users.
