The roll-out of the Android 4.4.3 KitKat update via OTA method is now almost complete for the Nexus devices. There were still some devices, including the popular Nexus 7 2012 3G tablet, that waits for the Android 4.4.3 update.
The good news is that even the Nexus 7 2012 3G receives this new update, as well as what has recently become available for the other Nexus devices, and that can be installed either manually or automatically.
Until now the Nexus devices, who have started to receive an update to Android 4.4.3 via OTA, are Nexus 7 2013 WiFi, Nexus 5, Nexus 4 and Nexus 10 and now we can also add to the list Nexus 7 2012 3G.
Android 4.4.3 adds many bug fixes, small updates to the Dialer and People apps, performance improvements and various adjustments.
It then waits for the release of the OTA only for another two Nexus devices Nexus 7 LTE 2013 and Nexus 7 2012 Wi-Fi.
As always you can check if your Nexus is receiving the latest update of Android, heading into Settings -> About phone / tablet -> System updates, having a stable WiFi connection.
Please note that OTA updates are released gradually over a short period and that, therefore, it may take several days for your Nexus detects the actual presence of OTA.
An XDA user succeeded to catch the update .zip file and make it accessible on the XDA-Developers forums. The over-the-air file is for the GSM/HSPA+ (3G) version of the Nexus 7 (2012) and brings the firmware to number KTU84L. Download from here KTU84L Android 4.4.3 for Nexus 7 2012 3G, update for the devices coming from build KOT49H.
This is an incremental update, not a factory image, and your device need to be on Android 4.4.2 firmware number KOT49H, in order for the update to run. Side loading the OTA file will not erase user data.
In the case you do not want to wait for the arrival of the OTA update, you can still manually install Android 4.4.3 on your device.
