If you were beginning to think that your good ole trusty Nexus 7 2012 OG edition was already going to be End Of Lifed by Google, luckily you were wrong. Google finally began the roll out for 4.4.3 on the first Nexus 7 today! This means that all of the devices less than two years old in the Nexus line have been upgraded to the latest and greatest version with the only exception being the Data Enabled Nexus 7 2013. To grab the update now just head to settings, about tablet, and check for updates. This is rolling out in increments, but you can grab the OTA for manually flashing now. XDA user oldblue 910 has kept a running archive of all the updates for both the 3g and wifi models of the Nexus 7 2012. So far the 3g OTA has been captured and is mirrored for download. The wifi version should be ready for download pretty soon. Head to the link below for the download. Once downloaded just boot into recovery mode to flash.
Via Nexus 7 OTA