The latest Android 4.4.3 KitKat update is rolling out now to the Nexus 4, Nexus 5, Nexus 7, Nexus 10 and other Google Play Edition devices that’s sold in selected markets. If you still haven’t gotten the update yet, here’s how you can force update manually.
Before you proceed, make sure you are using the official Android 4.4.2 version which was obtained over the air (OTA). Also make sure that the firmware version below matches your current device accordingly. You can download the Android 4.4.3 update from the links below.
Nexus 4 (Android 4.4.2 (KOT49H) to 4.4.3 (KTU48L)
Nexus 5 Android 4.4.2 (KOT49H) to 4.4.3 (KTU84M)
Nexus 7 (2013 WiFi) Android 4.4.2 (KOT49H) to 4.4.3 (KTU84L)
Nexus 10 Android 4.4.2 (KOT49H) to 4.4.3 (KTU84L)
To flash your Nexus device, you would need to install the Android SDK on your computer and run a few command lines to start the update. The folks at Android Central have published a comprehensive step by step guide over here. Good luck and please proceed only if you are absolutely sure on what you’re doing.