As per source , Google has released a small update for the Nexus 7 (2013) LTE upgrading the Android version number to Android 4.3.1. Basically , this is the initial actual step up for the newly-released tablet and the first device to go above Android 4.3 Jelly Bean. While the change-log does not give any intricate details and the new build number JLS36I is only a slight different from the actual shipping version of JLS36C.
Approaching the release of Android 4.4 KitKat a strong and affirmative assumption can be made regarding the remaining updates which will basically be maintenance bug fixes in terms of Jelly Bean. There is no say about whether the other Nexus devices will receive the Android 4.3.1 update but we would be receiving an update very soon about the same.